How Do You Lower CYA?

[Sherra]

I'd do a 50% drain & refill then re-test your CYA...if it's still higher than you want it, then do another 50% drain & refill. A 50% drain/refill should lower your CYA by 50%.

[cheshamjim]

Thanks, all. I was afraid this is the answer I'd get.

It seems that with my installation, I can only get by with a 30% drain at any one time. Think I'll wait until its time to close the pool.

-Jim

[Sherra]

One option is to get a really big plastic tarp (wide enough & long enough to cover your pool plus about 10 feet added to each measurement...just the cheap roll you can get at any home improvement place for a few bucks) and use that as a membrane between the two layers of water (the pool water beneath and the fresh water on top). You can theoretically do a 100% drain/refill that way without any damage to your liner. It's been discusses several times on the board. I don't know if anyone's actually DONE it on the group, but I remember seeing that someone had SEEN it done.