diff --git a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/PBasic.cpp b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/PBasic.cpp
index 53dda855..0b7b68dc 100644
--- a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/PBasic.cpp
+++ b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/PBasic.cpp
@@ -24,6 +24,16 @@
 #define toklength       20
 typedef long chset[9];
 
+#if defined(_MSC_VER) && (_MSC_VER <= 1400) // VS2005
+#  define nullptr NULL
+#endif
+
+#if __cplusplus < 201103L // Check if C++ standard is pre-C++11
+#  ifndef nullptr
+#    define nullptr NULL
+#  endif
+#endif
+
 #if defined(PHREEQCI_GUI)
 #ifdef _DEBUG
 #define new DEBUG_NEW
diff --git a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
index 7724d062..917353da 100644
--- a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
+++ b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/basicsubs.cpp
@@ -12,6 +12,16 @@
 #include "Solution.h"
 #include "Parser.h"
 
+#if defined(_MSC_VER) && (_MSC_VER <= 1400) // VS2005
+#  define nullptr NULL
+#endif
+
+#if __cplusplus < 201103L // Check if C++ standard is pre-C++11
+#  ifndef nullptr
+#    define nullptr NULL
+#  endif
+#endif
+
 #if defined(PHREEQCI_GUI)
 #ifdef _DEBUG
 #define new DEBUG_NEW
diff --git a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/print.cpp b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/print.cpp
index 033d4899..4aa70fb6 100644
--- a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/print.cpp
+++ b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/print.cpp
@@ -15,6 +15,16 @@
 #include "Solution.h"
 #include "Surface.h"
 
+#if defined(_MSC_VER) && (_MSC_VER <= 1400) // VS2005
+#  define nullptr NULL
+#endif
+
+#if __cplusplus < 201103L // Check if C++ standard is pre-C++11
+#  ifndef nullptr
+#    define nullptr NULL
+#  endif
+#endif
+
 #if defined(PHREEQCI_GUI)
 #ifdef _DEBUG
 #define new DEBUG_NEW
diff --git a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/transport.cpp b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/transport.cpp
index c49ee26b..6e69e8df 100644
--- a/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/transport.cpp
+++ b/src/IPhreeqcPhast/IPhreeqc/phreeqcpp/transport.cpp
@@ -52,6 +52,16 @@ struct MOLES_ADDED /* total moles added to balance negative conc's */
 } *moles_added;
 int count_moles_added;
 
+#if defined(_MSC_VER) && (_MSC_VER <= 1400) // VS2005
+#  define nullptr NULL
+#endif
+
+#if __cplusplus < 201103L // Check if C++ standard is pre-C++11
+#  ifndef nullptr
+#    define nullptr NULL
+#  endif
+#endif
+
 #if defined(PHREEQCI_GUI)
 #ifdef _DEBUG
 #define new DEBUG_NEW