Your pool should be drained 1/3 every year. If you have a sand filter, and you’re backwashing once per week, you are probably draining close to a third over the course of a year. Arizona has an 11 1/2 foot evaporation index. What that means to you is that your pool evaporates twice a year. Most pool owners have an auto-fill that automatically refills their pool as water evaporates. On a hot, windy Arizona day, your pool can lose up to 1/2” of water. As the pool evaporates and refills, you are doubling the amount of Total Dissolved Solids (TDS) in the pool. Total Dissolved Solids (TDS) are the minerals that water picks up when going through the ground to reach the water aquifer. And as we all know, Arizona has really hard water. Every time your pool evaporates and refills, you’re doubling your TDS. So every year your pool water is getting harder, and harder, and harder. TDS fights against all of the chemicals you are adding to your pool to keep it clean and clear. As time goes on, you will end up using more and more chemicals just to keep your pool balanced.
