diff --git a/ChemistryLib/PhreeqcIO.cpp b/ChemistryLib/PhreeqcIO.cpp
index 42d4ec00fc2840d34925909de9b04d742f65fcba..38d9bde1ff006971b463fbfbc589a8bf79bab136 100644
--- a/ChemistryLib/PhreeqcIO.cpp
+++ b/ChemistryLib/PhreeqcIO.cpp
@@ -96,6 +96,8 @@ void setReactantMolality(Reactant& reactant,
                 .property(MaterialPropertyLib::PropertyType::volume_fraction)
                 .template initialValue<double>(pos, t);
 
+        (*reactant.volume_fraction)[chemical_system_id] = volume_fraction;
+
         auto const fluid_density =
             liquid_phase.property(MaterialPropertyLib::PropertyType::density)
                 .template initialValue<double>(pos, t);