Cya High Or Low

[wilbanks51]

I've read that to remedy cloudy water, you must raise the CYA. Now, I just read a reply that stated that if the CYA is too high it will cause cloudy water. Wow. I don't know what to do. So, if the CYA is too high, how do you lower the CYA?

[chem geek]

By partial drain/refill -- that is, by water dilution. High CYA by itself does not cause cloudy water. It's having the FC/CYA ratio be too low that allows algae to grow faster than chlorine can kill it. So if you continued to use stabilized chlorine such as Trichlor tabs then the CYA would climb and if you didn't raise your FC level proportionately, then algae can grow and make the water dull/cloudy before a full-fledged green bloom (depending on algae species).

You wouldn't just lower your CYA level, but you also need to SLAM (shock level and maintain) your pool to kill off the algae. Doing that after lowering the CYA level, if you can do so quickly, will use less chlorine but I'd boost the FC up now at least some anyway while you are lowering your CYA level.