diff --git a/phreeqcpp/basicsubs.cpp b/phreeqcpp/basicsubs.cpp
index 758112f9..a21f34d5 100644
--- a/phreeqcpp/basicsubs.cpp
+++ b/phreeqcpp/basicsubs.cpp
@@ -195,7 +195,7 @@ diff_c(const char *species_name)
 		g = s_ptr->dw;
 		if (s_ptr->dw_t)
 				g *= exp(s_ptr->dw_t / tk_x - s_ptr->dw_t / 298.15);
-		g *= viscos_0_25 / viscos;
+		g *= viscos_0_25 / viscos * tk_x / 298.15;
 	}
 	else
 	{
@@ -218,7 +218,7 @@ setdiff_c(const char *species_name, double d)
 		g = s_ptr->dw;
 		if (s_ptr->dw_t)
 				g *= exp(s_ptr->dw_t / tk_x - s_ptr->dw_t / 298.15);
-		g *= viscos_0_25 / viscos;
+		g *= viscos_0_25 / viscos * tk_x / 298.15;;
 	}
 	else
 	{
@@ -2457,7 +2457,7 @@ total(const char *total_name)
 		return (total_o_x / mass_water_aq_x);
 	}
 	std::string noplus = total_name;
-	replace(noplus, "+", "");
+	replace(noplus, "(+", "(");
 	master_ptr = master_bsearch(noplus.c_str());
 	t = 0.0;
 	if (master_ptr == NULL)
@@ -2528,7 +2528,7 @@ total_mole(const char *total_name)
 		return (total_o_x);
 	}
 	std::string noplus = total_name;
-	replace(noplus, "+", "");
+	replace(noplus, "(+", "(");
 	master_ptr = master_bsearch(noplus.c_str());
 	t = 0.0;
 	if (master_ptr == NULL)
diff --git a/phreeqcpp/common/Parser.cxx b/phreeqcpp/common/Parser.cxx
index db7d3556..4f6665ae 100644
--- a/phreeqcpp/common/Parser.cxx
+++ b/phreeqcpp/common/Parser.cxx
@@ -899,7 +899,7 @@ CParser::STATUS_TYPE CParser::parse_couple(std::string & token)
 		return PARSER_OK;
 	}
 
-	while (Utilities::replace("+", "", token));
+	while (Utilities::replace("(+", "(", token));
 
 	std::string::iterator ptr = token.begin();
 	std::string elt1;
diff --git a/phreeqcpp/tidy.cpp b/phreeqcpp/tidy.cpp
index 4c95089b..1c9c0884 100644
--- a/phreeqcpp/tidy.cpp
+++ b/phreeqcpp/tidy.cpp
@@ -1825,7 +1825,7 @@ tidy_punch(void)
 		{
 			std::pair< std::string, void *> &pair_ptr = current_selected_output->Get_totals()[i];
 			std::string noplus = pair_ptr.first;
-			replace(noplus, "+", "");
+			replace(noplus, "(+", "(");
 			pair_ptr.second = master_bsearch(noplus.c_str());
 		}
 
diff --git a/phreeqcpp/utilities.cpp b/phreeqcpp/utilities.cpp
index d7989864..67a030ee 100644
--- a/phreeqcpp/utilities.cpp
+++ b/phreeqcpp/utilities.cpp
@@ -660,7 +660,7 @@ parse_couple(char *token)
 		str_tolower(token);
 		return (OK);
 	}
-	while (replace("+", "", token) == TRUE);
+	while (replace("(+", "(", token) == TRUE);
 	cptr = token;
 	get_elt(&cptr, elt1, &e1);
 	if (*cptr != '(')
@@ -848,9 +848,10 @@ replace(const char *str1, const char *str2, char *str)
 void Phreeqc::
 replace(std::string &stds, const char* str1, const char* str2)
 {
-	size_t pos;
+	size_t pos, l;
+	l = strlen(str1);
 	while ((pos = stds.find(str1)) != std::string::npos) {
-		stds.replace(pos, 1, str2);
+		stds.replace(pos, l, str2);
 	}
 }
 /* ---------------------------------------------------------------------- */