diff --git a/tests/test_solution.py b/tests/test_solution.py
index 305589d3..c52ea155 100644
--- a/tests/test_solution.py
+++ b/tests/test_solution.py
@@ -273,6 +273,12 @@ def test_charge_balance(s3, s5, s5_pH, s6, s6_Ca):
     s.equilibrate()
     assert s.balance_charge == "Na[+1]"
 
+    s = Solution({"Na+": "2 mM", "Cl-": "1 mM"}, balance_charge="auto")
+    assert s.balance_charge == "Cl[-1]"
+    assert np.isclose(s.charge_balance, 0, atol=1e-8)
+    s.equilibrate()
+    assert s.balance_charge == "Cl[-1]"
+
 
 def test_alkalinity_hardness(s3, s5, s6):
     assert np.isclose(s3.hardness, 0)