What is the white deposit on my pool tile?
Calcium scale (hard water build up) Calcium is a natural occurring mineral found in water. Here in the Desert Southwest the water is considered “hard” because it contains high levels of calcium and magnesium. When you visit Lake Mead you notice the white line around the mountains where the water level used to be, that white line is calcium the same as the calcium buildup you see around your pool tile. Hard water builds up on the pool tile where the air and the water meet when evaporation occurs. The mineral deposits left on the pool tile begin to accumulate and build up causing the white line to appear.
