diff --git a/ChemistryLib/PhreeqcKernel.cpp b/ChemistryLib/PhreeqcKernel.cpp
index 5648119467f8249c8a0d51fab6026b9d8bb4351d..2d9cdf19345c7741ada6374c027964d8169f655f 100644
--- a/ChemistryLib/PhreeqcKernel.cpp
+++ b/ChemistryLib/PhreeqcKernel.cpp
@@ -26,7 +26,7 @@ PhreeqcKernel::PhreeqcKernel(
     std::size_t const num_chemical_systems,
     std::vector<std::pair<int, std::string>> const&
         process_id_to_component_name_map,
-    std::string const database,
+    std::string const& database,
     AqueousSolution aqueous_solution,
     std::unique_ptr<EquilibriumReactants>&& equilibrium_reactants,
     std::unique_ptr<Kinetics>&& kinetic_reactants,
diff --git a/ChemistryLib/PhreeqcKernel.h b/ChemistryLib/PhreeqcKernel.h
index c7b62005b806f640687f5f6a6259399f000a8f16..de5ed34a844dce581ef8ed52d7413731bfbc21de 100644
--- a/ChemistryLib/PhreeqcKernel.h
+++ b/ChemistryLib/PhreeqcKernel.h
@@ -35,7 +35,7 @@ public:
     PhreeqcKernel(std::size_t const num_chemical_systems,
                   std::vector<std::pair<int, std::string>> const&
                       process_id_to_component_name_map,
-                  std::string const database,
+                  std::string const& database,
                   AqueousSolution aqueous_solution,
                   std::unique_ptr<EquilibriumReactants>&& equilibrium_reactants,
                   std::unique_ptr<Kinetics>&& kinetic_reactants,