Calcium hardness is not a calcium chloride reading. Calcium hardness is a measure of the calcium ions in the water and is expressed as calcium carbonate. It is what we call hardness in water. The Hardness level in your pool water should be between 200 and 400 ppm. The minimum level to attain water balance is 150 ppm. The chemical calcium chloride is used to increase the hardness level in the water.

The salt level in your pool water is a measure of the chloride ion. It is also called salinity. Chlorides come from sodium chloride and chlorine that is no longer an active killer. Chlorine becomes chloride. So all of the chlorine you add to a pool eventually becomes chloride. To a very small extent, chloride can come from calcium chloride if it was added to increase hardness.

Most chlorine generators need a salt or chloride level between 2500 and 5000 ppm. This is measured with a chloride test. usually once you add this amount of salt to the water, you only have to add more or check it a couple of times a year. The chloride you add to the water is recycled. It works this way. You add salt and the chloride is converted to the killing form of chlorine (called hypochlorous acid - HOCl) then the HOCl reverts back to chloride where the chlorine generator can convert it back into HOCl. And it starts all over again.

Even though chloride is in the name of the chemical we use for increasing hardness (calcium chloride), do not confuse it with sodium chloride that we use for increasing the salt content of the water.