diff --git a/Phreeqc.cpp b/Phreeqc.cpp
index 69b43378..b6ac835c 100644
--- a/Phreeqc.cpp
+++ b/Phreeqc.cpp
@@ -711,9 +711,6 @@ void Phreeqc::init(void)
 	/*----------------------------------------------------------------------
 	*   Elements
 	*---------------------------------------------------------------------- */
-	elements                 = NULL;
-	count_elements           = 0;
-	max_elements             = MAX_ELEMENTS;
 	element_h_one            = NULL;
 	/*----------------------------------------------------------------------
 	*   Element List
@@ -1644,25 +1641,15 @@ Phreeqc::InternalCopy(const Phreeqc *pSrc)
 	/*----------------------------------------------------------------------
 	*   Elements
 	*---------------------------------------------------------------------- */
-	//max_elements = pSrc->max_elements;
-	//elements = (struct element **) free_check_null(elements);
-	//elements = (struct element **) PHRQ_malloc((size_t)max_elements * sizeof(struct element));
-	space((void **)((void *)&elements), pSrc->max_elements, &max_elements,
-		sizeof(struct element *));
-	count_elements = 0;
-	for (int i = 0; i < pSrc->count_elements; i++)
+	for (int i = 0; i < (int)pSrc->elements.size(); i++)
 	{
-		string_hsave(pSrc->elements[i]->name);
-		struct element *elt_ptr = element_store(pSrc->elements[i]->name);
+
+		const char * ptr = string_hsave(pSrc->elements[i]->name);
+		struct element *elt_ptr = element_store(ptr);
 		elt_ptr->gfw = pSrc->elements[i]->gfw;
 	}
 	element_h_one = element_store("H(1)");
-	/*
-	elements                 = NULL;
-	count_elements           = 0;
-	max_elements             = MAX_ELEMENTS;
-	element_h_one            = NULL;
-	*/
+
 	/*----------------------------------------------------------------------
 	*   Element List
 	*---------------------------------------------------------------------- */
diff --git a/Phreeqc.h b/Phreeqc.h
index ee8cd26e..8f85741e 100644
--- a/Phreeqc.h
+++ b/Phreeqc.h
@@ -1457,10 +1457,7 @@ protected:
 	/*----------------------------------------------------------------------
 	*   Elements
 	*---------------------------------------------------------------------- */
-
-	struct element **elements;
-	int count_elements;
-	int max_elements;
+	std::vector<struct element*> elements;
 	struct element *element_h_one;
 
 	/*----------------------------------------------------------------------
diff --git a/mainsubs.cpp b/mainsubs.cpp
index eb86b22d..80acd672 100644
--- a/mainsubs.cpp
+++ b/mainsubs.cpp
@@ -60,9 +60,6 @@ initialize(void)
 		cell_data[i].print = FALSE;
 	}
 
-	space((void **) ((void *) &elements), INIT, &max_elements,
-		  sizeof(struct element *));
-
 	space((void **) ((void *) &elt_list), INIT, &max_elts,
 		  sizeof(struct elt_list));
 
@@ -103,7 +100,7 @@ initialize(void)
  */
 	hcreate_multi((unsigned) max_logk, &logk_hash_table);
 	hcreate_multi((unsigned) MAX_ELTS, &master_isotope_hash_table);
-	hcreate_multi((unsigned) max_elements, &elements_hash_table);
+	hcreate_multi((unsigned) MAX_ELTS, &elements_hash_table);
 	hcreate_multi((unsigned) max_s, &species_hash_table);
 	hcreate_multi((unsigned) max_phases, &phases_hash_table);
 	// one save_values
diff --git a/structures.cpp b/structures.cpp
index 988b05a6..8a008813 100644
--- a/structures.cpp
+++ b/structures.cpp
@@ -81,11 +81,10 @@ clean_up(void)
 
 /* elements */
 
-	for (j = 0; j < count_elements; j++)
+	for (j = 0; j < (int)elements.size(); j++)
 	{
 		elements[j] = (struct element *) free_check_null(elements[j]);
 	}
-	elements = (struct element **) free_check_null(elements);
 
 /* solutions */
 	Rxn_solution_map.clear();
@@ -312,7 +311,6 @@ clean_up(void)
 #endif
 	title_x = (char *) free_check_null(title_x);
 	last_title_x.clear();
-	count_elements = 0;
 	count_master = 0;
 	count_phases = 0;
 	count_s = 0;
@@ -407,7 +405,6 @@ element_store(const char *element)
  *   Returns:
  *      The address of an elt structure that contains the element data.
  */
-	int n;
 	struct element *elts_ptr;
 	ENTRY item, *found_item;
 	char token[MAX_LENGTH];
@@ -428,8 +425,9 @@ element_store(const char *element)
  *   Save new elt structure and return pointer to it
  */
 	/* make sure there is space in elements */
-	elements[count_elements] =
-		(struct element *) PHRQ_malloc((size_t) sizeof(struct element));
+	size_t count_elements = elements.size();
+	elements.resize(count_elements + 1);
+	elements[count_elements] = (struct element *) PHRQ_malloc((size_t) sizeof(struct element));
 	if (elements[count_elements] == NULL)
 		malloc_error();
 	/* set name pointer in elements structure */
@@ -438,24 +436,18 @@ element_store(const char *element)
 	elements[count_elements]->master = NULL;
 	elements[count_elements]->primary = NULL;
 	elements[count_elements]->gfw = 0.0;
-	n = count_elements++;
-	if (count_elements >= max_elements)
-	{
-		space((void **) ((void *) &elements), count_elements, &max_elements,
-			  sizeof(struct element *));
-	}
 /*
  *   Update hash table
  */
-	item.key = elements[n]->name;
-	item.data = (void *) elements[n];
+	item.key = elements[count_elements]->name;
+	item.data = (void *) elements[count_elements];
 	found_item = hsearch_multi(elements_hash_table, item, ENTER);
 	if (found_item == NULL)
 	{
 		error_string = sformatf( "Hash table error in element_store.");
 		error_msg(error_string, CONTINUE);
 	}
-	return (elements[n]);
+	return (elements[count_elements]);
 }
 
 /* **********************************************************************
diff --git a/tidy.cpp b/tidy.cpp
index 83af5b16..44e19e2b 100644
--- a/tidy.cpp
+++ b/tidy.cpp
@@ -154,11 +154,10 @@ tidy_model(void)
 
 /* master species */
 		qsort(master, (unsigned) count_master, sizeof(struct master *), master_compare);
-
 /* elements */
-		qsort(elements, (size_t) count_elements, (size_t) sizeof(struct element *), element_compare);
+		qsort(elements.data(), elements.size(), sizeof(struct element *), element_compare);
 /* phases */
-		qsort(phases, (size_t) count_phases, (size_t) sizeof(struct phase *), phase_compare);
+		qsort(phases, (size_t) count_phases, sizeof(struct phase *), phase_compare);
 
 	}
 
@@ -2429,7 +2428,7 @@ tidy_species(void)
 /*
  *   Set pointer in element to master species
  */
-	for (i = 0; i < count_elements; i++)
+	for (i = 0; i < (int)elements.size(); i++)
 	{
 		elements[i]->master = master_bsearch(elements[i]->name);
 		if (elements[i]->master == NULL)
diff --git a/transport.cpp b/transport.cpp
index 0bacb84b..c2e84bc0 100644
--- a/transport.cpp
+++ b/transport.cpp
@@ -135,7 +135,7 @@ transport(void)
 			ct[i].m_s = NULL;
 			ct[i].v_m_size = ct[i].J_ij_size = ct[i].m_s_size = 0;
 		}
-		count_moles_added = count_elements;
+		count_moles_added = (int)elements.size();
 		moles_added = (struct MOLES_ADDED *) PHRQ_malloc((size_t) (count_moles_added)* sizeof(struct MOLES_ADDED));
 		if (moles_added == NULL)
 			malloc_error();