Is cyanuric acid (CYA) only reduced through the removal/replacement of pool water, or does it break down or decay naturally over time (e.g. during the months the pool is closed)?
My lame test strips (a real test kit is still on its way to me) indicate I probably have a CYA level of at least 100. After years of dichlor and trichlor abuse, I'm surprised it's not higher. Who knows, it may well be once I can do a real test. Anyhow I plan to do a partial drain/refill but don't want to take the water level down more than 1 foot at a time (vinyl liner), and probably don't have the time to do more than 2 intentional drain/refills this season. And of course there will be some removal/replacement due to backwashing, vacuuming, etc. But I was curious if CYA breaks down on its own over a lengthy amount of time.