CYA Loss


Well-known member
Oct 8, 2015
San Diego, Ca.
Every year I have to add 8 lbs of CYA to maintain the 70ppm. There pool is only used a couple of times per year so splash out is not an issue. I don't have a DE filter.

Somehow I got the impression that CYA didn't leave the pool unless you drained water?

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Actually, while water exchange is the primary way to lower CYA, it also drops slowly throughout the year by degradation within the chemical exchange processes. Our pools seem to deplete about 3-5 ppm per month (give or take) depending on the pool itself and its environmental conditions. I pump up my CYA for summer, but after the winter find myself having to add some as well. So you're not alone.