diff --git a/Tests/Data/Elliptic/square_100x100_ComponentTransport/square_1e4_heterogeneity.prj b/Tests/Data/Elliptic/square_100x100_ComponentTransport/square_1e4_heterogeneity.prj
index 42f8bf071ad1ab286932cb0eeaab4488c41f6c9a..135620b68cc5eeae2bb43a56eb203f45815cfca9 100644
--- a/Tests/Data/Elliptic/square_100x100_ComponentTransport/square_1e4_heterogeneity.prj
+++ b/Tests/Data/Elliptic/square_100x100_ComponentTransport/square_1e4_heterogeneity.prj
@@ -11,34 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -64,12 +36,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -125,11 +124,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_1d.prj b/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_1d.prj
index 74774f0ac77106358a2eacd628cf81f2a1d2a0fa..156f3cfd75c569fe1a41405651d38ea4e25e1f5c 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_1d.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_1d.prj
@@ -12,34 +12,6 @@
                 <concentration>Cs</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -65,12 +37,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -177,11 +176,6 @@
             <type>Constant</type>
             <value>0.38</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>retardation</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_2d.prj b/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_2d.prj
index aff238c3f49dad3eb30c0d73a31612cc19716f03..7448f129302b604322ff2653c5f72f64e26fd7b9 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_2d.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ConTracer/ConTracer_2d.prj
@@ -12,34 +12,6 @@
                 <concentration>Cs</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 -9.81</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -65,12 +37,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -177,11 +176,6 @@
             <type>Constant</type>
             <value>0.38</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>retardation</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/MassConservation/mass_conservation.prj b/Tests/Data/Parabolic/ComponentTransport/MassConservation/mass_conservation.prj
index e91dd0d8c53185268fd548d40809228f1600519e..4745fa4653a61020287648ebed53e99551cada72 100644
--- a/Tests/Data/Parabolic/ComponentTransport/MassConservation/mass_conservation.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/MassConservation/mass_conservation.prj
@@ -15,36 +15,6 @@
             <pressure>pressure</pressure>
             </process_variables>
             <non_advective_form>true</non_advective_form>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1e3</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                </permeability>
-                <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                </porosity>
-                <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -70,12 +40,46 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1e3</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>transversal_dispersivity</name>
                     <type>Constant</type>
@@ -132,11 +136,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/EquilibriumPhase/calcite.prj b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/EquilibriumPhase/calcite.prj
index 4f65ea2e33e7eb6fe4fbac692807b0074157fd03..85db351b60fcfda943ef728fc4a5bbd2e8f8475c 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/EquilibriumPhase/calcite.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/EquilibriumPhase/calcite.prj
@@ -16,34 +16,6 @@
                 <concentration>H</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,6 +41,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -84,6 +61,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -99,6 +81,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -114,6 +101,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -129,12 +121,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -388,11 +407,6 @@
             <type>Constant</type>
             <value>0.32</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac.prj b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac.prj
index 1c328b75223eaafc8a2fa24b2f59a9f8e82941ca..866a244a15b18be83c790f02eef0522208b9ca58 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac.prj
@@ -14,34 +14,6 @@
                 <concentration>Syntheticb</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -67,6 +39,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -82,6 +59,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -97,12 +79,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -323,11 +332,6 @@
             <type>Constant</type>
             <value>1</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac_flag_formula.prj b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac_flag_formula.prj
index 9ca2291e387e64ae10825985cc1e6a1e0d65f5f8..e27bf2c6fb82e7d21bb29cd175c481f88bcb4032 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac_flag_formula.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant/1d_isofrac_flag_formula.prj
@@ -14,34 +14,6 @@
                 <concentration>Syntheticb</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -67,6 +39,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -82,6 +59,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -97,12 +79,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -300,11 +309,6 @@
             <type>Constant</type>
             <value>1</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2.prj b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2.prj
index 49b98a3b51c2f9a82a43a7a74a1bbcac51aaa180..494c4a8f42e649b39c76e56e70303684d6b1e8dc 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2.prj
@@ -15,34 +15,6 @@
                 <concentration>Productd</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -68,6 +40,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -83,6 +60,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -98,6 +80,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -113,12 +100,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -347,11 +361,6 @@
             <type>Constant</type>
             <value>1</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>retardation</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2_2d.prj b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2_2d.prj
index a5e8d3ac4509248e6557e9afc4179f69df990abf..47c29e735b6c91b1b715616531a98361c648f7d0 100644
--- a/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2_2d.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/ReactiveTransport/KineticReactant_AllAsComponents/KineticReactant2_2d.prj
@@ -15,34 +15,6 @@
                 <concentration>Productd</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -68,6 +40,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -83,6 +60,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -98,6 +80,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -113,12 +100,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -347,11 +361,6 @@
             <type>Constant</type>
             <value>1</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>retardation</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionAndStorage.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionAndStorage.prj
index 8f952f09d8b5aaef921cd89e1d8178c1e9698579..9cae2ee138bc5188dddff371bdcde818a28acaa9 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionAndStorage.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionAndStorage.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.0</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -156,11 +149,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly.prj
index 41ef82138142b8093c07447ec7304b2bab454a6c..a6a0a9eb681d57964df2d279998a2f3a71a5dbca 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly.prj
@@ -11,50 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -80,12 +36,46 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -156,11 +146,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly_3Components.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly_3Components.prj
index 0a5ff0d6e70fb41c33968a83eeb76b8769950756..54f0576602a48f1954b5265587e73a6201fee950 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly_3Components.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/ConcentrationDiffusionOnly_3Components.prj
@@ -13,50 +13,6 @@
                 <concentration>Cl</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,6 +38,11 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -97,6 +58,11 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -112,12 +78,46 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -190,11 +190,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvection.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvection.prj
index 0056dcdcaddf1c8b24421448949e10c0774cdf1e..9adfed90e52b51961ea8893791896328bffd7a45 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvection.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvection.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -175,11 +168,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDecay.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDecay.prj
index fc16f4fad8f1187c28d243991db71fbe9ff0b87a..8c7239ca5a6323e716afe9dd1f8519e6e231f138 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDecay.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDecay.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>2e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>2e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -175,11 +168,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersion.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersion.prj
index 3dd41cb015051dad80f5aacd4b5193e214e9fb8a..f34b01269e4ab83707972fd3840e1ae47f7eaa00 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersion.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersion.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>2e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>2e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -175,11 +168,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
index bb257b501f6e31e1c049d93baf3a62bcccf4adac..2eb4a436e39de9d7ba2945ce465175f5d0e88655 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -175,11 +168,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndGravityAndDispersionHalf.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndGravityAndDispersionHalf.prj
index 23d2d4d88a088b6c196c27d0e5c96d770069330b..564c74d0f0b8bfcb6dcb629f2c48a6fb160d73e1 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndGravityAndDispersionHalf.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/DiffusionAndStorageAndGravityAndDispersionHalf.prj
@@ -11,52 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>1</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-                <porous_medium id="1">
-                    <permeability>
-                        <permeability_tensor_entries>kappa2</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 -1</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -82,12 +36,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>1</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -151,11 +144,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3.prj
index 3e0e3815b9e2d91354dcef96009e0e6e1b0e27cc..910a3cb2dc435a83caa62e43fa73daf5c637ca3d 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3.prj
@@ -16,34 +16,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-		    <density>
-			    <type>Constant</type>
-			    <value>1e3</value>
-                    </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +41,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -140,11 +139,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3_advective_form.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3_advective_form.prj
index 7b47c359800aa436b5578e9e4b5e015dfdad0021..42a66eb92b8584daaf373c25519c0134f4123866 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3_advective_form.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/open_boundary_component-transport_cube_1e3_advective_form.prj
@@ -15,34 +15,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-		    <density>
-			    <type>Constant</type>
-			    <value>1e3</value>
-                    </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -68,12 +40,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -139,11 +138,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/surfaceflux_component-transport_cube_1e3.prj b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/surfaceflux_component-transport_cube_1e3.prj
index 18cbde823388df8a1d834f4f9b91320f34e05902..4a972da2b84f02cea33faa33fadca5dfc7f2b341 100644
--- a/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/surfaceflux_component-transport_cube_1e3.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/SimpleSynthetics/surfaceflux_component-transport_cube_1e3.prj
@@ -15,36 +15,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -75,12 +45,46 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -151,11 +155,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionAndStorage.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionAndStorage.prj
index 3fc02b21c74ac5a669efdb847c30b7287e3d4fb1..12cf4c8ae2d2d2a7e70904578d8167e63ca0aded 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionAndStorage.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionAndStorage.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.0</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -192,11 +199,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionOnly.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionOnly.prj
index 16d51163866eb470ecd2e47fc9fcd6d0a62bd3d5..149934eeeedb40fa844d469feeae85d4a4f8bae2 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionOnly.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/ConcentrationDiffusionOnly.prj
@@ -12,36 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -67,12 +37,46 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -179,11 +183,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvection.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvection.prj
index 68c4ae6012e6400f33c2cf009cdd5762efed06b3..9236f69e0de505f6f608e436cc13ce59cd1560f3 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvection.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvection.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -235,11 +242,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDecay.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDecay.prj
index c2db344e287e42badd5ef9524d6d147b734089f7..0b9ff4a7428658859b6d26175e56df8ddcd3791c 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDecay.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDecay.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>2e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>2e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -235,11 +242,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion.prj
index 07a534e546190c4b8b2b7ebc671a83af003e1460..1baac43487aa9ffcd6cc716e7c76afe5129531ad 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>2e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>2e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -235,11 +242,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
index 937e0048b0281605719e783c142cb30add274ca6..697bded4c6476e0dcd66e8832975bbb84ca1e60e 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersionHalf.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -235,11 +242,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion_3Components.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion_3Components.prj
index 49a1c784536a16ea9602aff7429c74072317a859..cc0c258826d0b8bee36edc1332727452ce22f77f 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion_3Components.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndAdvectionAndDispersion_3Components.prj
@@ -14,38 +14,6 @@
                 <concentration>Cl</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>0.026</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0.5</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>2e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -71,6 +39,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -86,6 +59,11 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                         <component>
@@ -101,12 +79,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.026</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0.5</reference_condition>
+                                    <slope>2e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -391,11 +408,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndGravityAndDispersionHalf.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndGravityAndDispersionHalf.prj
index 27f85ee51c3580491d652917971c990b90426349..6271b2f3ddd0e7799e677c79b6ecf518af421bbc 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndGravityAndDispersionHalf.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/DiffusionAndStorageAndGravityAndDispersionHalf.prj
@@ -12,38 +12,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_concentration_difference_ratio>1</fluid_density_concentration_difference_ratio>
-                    <reference_pressure>0</reference_pressure>
-                    <fluid_density_pressure_difference_ratio>5e-5</fluid_density_pressure_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>1e-5</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 -1</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +37,51 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>1</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5e-5</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -183,11 +190,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/surfaceflux_component-transport_cube_1e3.prj b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/surfaceflux_component-transport_cube_1e3.prj
index 78fd1caa51f75839f6325866ef1b7cc8ace48788..e613f06cf3605c22a85b19e9fbf3d8eded744494 100644
--- a/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/surfaceflux_component-transport_cube_1e3.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/StaggeredScheme/surfaceflux_component-transport_cube_1e3.prj
@@ -16,36 +16,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.0</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -76,12 +46,46 @@
                                     <type>Constant</type>
                                     <value>0</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.0</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -193,11 +197,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/Theis/theis.prj b/Tests/Data/Parabolic/ComponentTransport/Theis/theis.prj
index 0a44540a848a66d73e80bc8a3cfde29b1f969143..67380a662e9302c354561995fa0aaad654dbdb01 100644
--- a/Tests/Data/Parabolic/ComponentTransport/Theis/theis.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/Theis/theis.prj
@@ -22,42 +22,6 @@
                 <property_name>flux</property_name>
                 <output_mesh>out_abstraction_whole_surf_flux.vtu</output_mesh>
             </calculatesurfaceflux> -->
-            <fluid>
-                <density>
-                    <type>ConcentrationAndPressureDependent</type>
-                    <fluid_density_concentration_difference_ratio>0</fluid_density_concentration_difference_ratio>
-                    <fluid_density_pressure_difference_ratio>5.0968E-08</fluid_density_pressure_difference_ratio>
-                    <reference_concentration>0</reference_concentration>
-                    <reference_pressure>0</reference_pressure>
-                    <reference_density>1000</reference_density>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity1</porosity_parameter>
-                    </porosity>
-                    <!-- The implementation of the ComponentTransport process
-                    is without Boussinesq approximations, thus, 'storage' is not
-                    used here, but should be set through S =thickness * gravity
-                    * porosity * d\rho / dp / rho.  -->
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 -9.81</specific_body_force>
         </process>
     </processes>
@@ -80,12 +44,60 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1000</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0</slope>
+                                </independent_variable>
+                                <independent_variable>
+                                    <variable_name>phase_pressure</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>5.0968E-08</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity1</parameter_name>
+                </property>
+                <!-- The implementation of the ComponentTransport process
+                is without Boussinesq approximations, thus, 'storage' is not
+                used here, but should be set through S =thickness * gravity
+                * porosity * d\rho / dp / rho.  -->
+                <!--property>
+                    <name>storage</name>
+                    <type>Constant</type>
+                    <value>0</value>
+                </property-->
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -185,11 +197,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/TracerSimulation/TracerSimulation.prj b/Tests/Data/Parabolic/ComponentTransport/TracerSimulation/TracerSimulation.prj
index 46380cbaadbec0d635ed1df1a73c2fe9d9abb27d..64d2edff1afdeb8387e3e732900bc71262bf207f 100644
--- a/Tests/Data/Parabolic/ComponentTransport/TracerSimulation/TracerSimulation.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/TracerSimulation/TracerSimulation.prj
@@ -12,34 +12,6 @@
                 <concentration>Cs</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <type>Constant</type>
-                        <permeability_tensor_entries>kappa</permeability_tensor_entries>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>porosity</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -65,12 +37,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>porosity</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -177,11 +176,6 @@
             <type>Constant</type>
             <value>0.2</value>
         </parameter>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/VariableNeumannBoundary/vdbc_input.prj b/Tests/Data/Parabolic/ComponentTransport/VariableNeumannBoundary/vdbc_input.prj
index b3e32118c6cfbf14b72f9a29316ddb980edbdeb1..d8dfc6e3b69365c45f0efb2fb85c4470b903cd90 100644
--- a/Tests/Data/Parabolic/ComponentTransport/VariableNeumannBoundary/vdbc_input.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/VariableNeumannBoundary/vdbc_input.prj
@@ -14,34 +14,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1000</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -67,12 +39,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -148,11 +147,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/elder/elder-python.prj b/Tests/Data/Parabolic/ComponentTransport/elder/elder-python.prj
index a2e4cfe320993e242617114657c4312752ee3954..f25c563652dc406bc4d598b05792a1cc8ca70f78 100644
--- a/Tests/Data/Parabolic/ComponentTransport/elder/elder-python.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/elder/elder-python.prj
@@ -14,36 +14,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1000</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.2</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <decay_rate>decay_rate</decay_rate>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
             <specific_body_force>0 0 -9.81</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +39,46 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay_rate</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1000</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.2</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -130,11 +134,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000.0</value>
-        </parameter>
         <parameter>
             <name>decay_rate</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/elder/elder.prj b/Tests/Data/Parabolic/ComponentTransport/elder/elder.prj
index ffb51345598b8cfc5e043bd9cab6cd3c1a3f0396..536703e4ff9501784ad40225e1e4f35bdbdc0f65 100644
--- a/Tests/Data/Parabolic/ComponentTransport/elder/elder.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/elder/elder.prj
@@ -11,40 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <!-- <density>
-                   <type>Constant</type>
-                   <value>1000</value>
-               </density> -->
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1000</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.2</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0.0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <decay_rate>decay_rate</decay_rate>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
             <specific_body_force>0 0 -9.81</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -70,12 +36,46 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay_rate</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1000</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.2</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -134,11 +134,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000.0</value>
-        </parameter>
         <parameter>
             <name>decay_rate</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/goswami/goswami_input.prj b/Tests/Data/Parabolic/ComponentTransport/goswami/goswami_input.prj
index 04b6359a141513e6854314b3c92d4b6981dc100d..159e40c0141a4a44bf72d2ce5ba12de96363e6aa 100644
--- a/Tests/Data/Parabolic/ComponentTransport/goswami/goswami_input.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/goswami/goswami_input.prj
@@ -14,36 +14,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>ConcentrationDependent</type>
-                    <reference_density>1000</reference_density>
-                    <reference_concentration>0</reference_concentration>
-                    <fluid_density_difference_ratio>0.701</fluid_density_difference_ratio>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 -9.81</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -69,12 +39,46 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Linear</type>
+                            <reference_value>1000</reference_value>
+                            <independent_variables>
+                                <independent_variable>
+                                    <variable_name>concentration</variable_name>
+                                    <reference_condition>0</reference_condition>
+                                    <slope>0.701</slope>
+                                </independent_variable>
+                            </independent_variables>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -150,11 +154,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_2D/ogs5_H_2d.prj b/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_2D/ogs5_H_2d.prj
index 1eeea9dd13a01b5e7f4cd768c378e048dd579e8d..40b914a0548c3210adb39fcdef52764dbf3a5766 100644
--- a/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_2D/ogs5_H_2d.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_2D/ogs5_H_2d.prj
@@ -11,34 +11,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -64,12 +36,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -125,11 +124,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>
diff --git a/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_3D/ogs5_H_3d.prj b/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_3D/ogs5_H_3d.prj
index 46310325d50081d7089cb13e907850fbf4faefb9..15e3d0ecc6283d8b199bd368a693d28971a170f2 100644
--- a/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_3D/ogs5_H_3d.prj
+++ b/Tests/Data/Parabolic/ComponentTransport/heterogeneous/ogs5_H_3D/ogs5_H_3d.prj
@@ -14,34 +14,6 @@
                 <concentration>Si</concentration>
                 <pressure>pressure</pressure>
             </process_variables>
-            <fluid>
-                <density>
-                    <type>Constant</type>
-                    <value>1e3</value>
-                </density>
-                <viscosity>
-                    <type>Constant</type>
-                    <value>1.0e-3</value>
-                </viscosity>
-            </fluid>
-            <porous_medium>
-                <porous_medium id="0">
-                    <permeability>
-                        <permeability_tensor_entries>kappa1</permeability_tensor_entries>
-                        <type>Constant</type>
-                    </permeability>
-                    <porosity>
-                        <type>Constant</type>
-                        <porosity_parameter>constant_porosity_parameter</porosity_parameter>
-                    </porosity>
-                    <storage>
-                        <type>Constant</type>
-                        <value>0</value>
-                    </storage>
-                </porous_medium>
-            </porous_medium>
-            <fluid_reference_density>rho_fluid</fluid_reference_density>
-            <decay_rate>decay</decay_rate>
             <specific_body_force>0 0 -9.81</specific_body_force>
             <secondary_variables>
                 <secondary_variable type="static" internal_name="darcy_velocity" output_name="darcy_velocity"/>
@@ -67,12 +39,39 @@
                                     <type>Constant</type>
                                     <value>1</value>
                                 </property>
+                                <property>
+                                    <name>decay_rate</name>
+                                    <type>Parameter</type>
+                                    <parameter_name>decay</parameter_name>
+                                </property>
                             </properties>
                         </component>
                     </components>
+                    <properties>
+                        <property>
+                            <name>density</name>
+                            <type>Constant</type>
+                            <value>1e3</value>
+                        </property>
+                        <property>
+                            <name>viscosity</name>
+                            <type>Constant</type>
+                            <value>1e-3</value>
+                        </property>
+                    </properties>
                 </phase>
             </phases>
             <properties>
+                <property>
+                    <name>permeability</name>
+                    <type>Parameter</type>
+                    <parameter_name>kappa1</parameter_name>
+                </property>
+                <property>
+                    <name>porosity</name>
+                    <type>Parameter</type>
+                    <parameter_name>constant_porosity_parameter</parameter_name>
+                </property>
                 <property>
                     <name>longitudinal_dispersivity</name>
                     <type>Constant</type>
@@ -128,11 +127,6 @@
         </output>
     </time_loop>
     <parameters>
-        <parameter>
-            <name>rho_fluid</name>
-            <type>Constant</type>
-            <value>1000</value>
-        </parameter>
         <parameter>
             <name>decay</name>
             <type>Constant</type>