diff --git a/ionize/Ion/BaseIon.py b/ionize/Ion/BaseIon.py
index e3b5ec0..2cdab8f 100644
--- a/ionize/Ion/BaseIon.py
+++ b/ionize/Ion/BaseIon.py
@@ -50,7 +50,7 @@ def __str__(self):
 
     def __hash__(self):
         """Return the hash value for the object."""
-        return hash(json.dumps(self._state))
+        return hash(self.serialize())
 
     def __eq__(self, other):
         """Test equality between two ions."""
diff --git a/ionize/tests.py b/ionize/tests.py
index 1c2c455..0840c4f 100644
--- a/ionize/tests.py
+++ b/ionize/tests.py
@@ -176,6 +176,16 @@ def test_equality(self):
         sol = Solution([hcl], [0.1])
         self.assertEqual(hcl, hcl2)
 
+    def test_hash(self):
+        for ion in self.database.keys():
+            ion1 = self.database[ion]
+            ion2 = self.database[ion]
+            ion1.context({'pH': 8, 'ionic_strength': 0.1, 'temperature': 28})
+            ion2.context({'pH': 9, 'ionic_strength': 0.05, 'temperature': 23})
+            self.assertTrue(hash(ion1)==hash(ion2),
+                            "Ions from database aren't identitcal.",
+                            )
+
     def test_serialize(self):
         for ion_name in self.database.keys():
             ion = self.database.load(ion_name)
@@ -365,6 +375,11 @@ def test_moderate(self):
         self.assertFalse(sol.moderate(), 'Unbuffered acid evaluated as safe.')
         self.assertTrue(sol.titrate('tris', 8).moderate(), 'Tris buffer evaluated as unsafe.')
 
+    def test_hash(self):
+        sol1 = Solution('chloride', 0.001)
+        sol2 = Solution('chloride', 0.001)
+        self.assertEqual(hash(sol1), hash(sol2))
+
 class TestNucleicAcid(unittest.TestCase):
 
     def test_mobility(self):