Calcium hardness

Calcium hardness protects pool surfaces. Water with too little calcium pulls it from plaster and grout, which causes etching and rough spots. Water with too much leaves white or gray scale on tile, in the heater, and inside the salt cell.

Heat makes scale worse, and North Texas summers are hot. Test at least monthly. To raise calcium, a pro adds calcium chloride. To lower it, the usual fix is a partial drain and refill with softer water. Your fill water matters here, so test it too. A Langelier index ties this number to the rest of the balance.