So I'm just going to jump right into it. A clients pool that we service jumped from a 50 cya to a hundred within two weeks about 3 months ago. (we use Taylor testing kits so its pretty accurate) The chlorine level was always a 10 but due to the high cya, algae starting blooming left and right. He has a tab feeder so we assumed the Chlorine tabs we were adding was spiking the cya. In response to this we drained half the pool and refilled it. After that we had a perfect 50 again, we also put two floaters in the pool and filled them with Cya free chlorine tabs. For awhile we would add one or two normal chlorine tabs into the feeder, but after a few weeks the cya started to rise again. We completely stopped adding the normal tabs into the feeder and just relied on the floaters. Since then the cya level is skyrocketing again with no end. And at this point we're not sure what to do. We could drain the pool again but I'm afraid the same thing will happen. I know there's chemicals out there that say they decrease cya, but all I've heard is bad reviews and more problems. If anyone has any input it would be greatly appreciated.