How to lower high cyanuric acid (CYA) levels?

[eruppert]

Is there any way to lower the level of Cyanuric acid, besides draining your pool?

Thanks,

Eric

[chem geek]

No, not really. Cyanuric Acid does not evaporate and is only readily removed via water dilution. There have been products in the past that attempted to remove it, but they created a cloudy mess since they were melamine which is the same chemical used in the CYA test to make the water cloudy.

CYA is slowly oxidized by chlorine, but in a pool that's normally pretty slow at around 2-3 ppm CYA per month. It goes away faster at higher Free Chlorine (FC) and higher pH, but it's still pretty slow and not practical. CYA can also go away from bacteria that convert it hopefully to nitrogen gas though it can instead get converted to ammonia -- again, not practical nor very controllable methods.

Sorry to be the bearer of bad news, but dilution is the solution to lowering CYA.

[CarlD]

chem geek is right. There IS another way to lower your CYA but the cure is far, FAR worse than the disease, so there's not much point to it.

[PoolDoc]

. . . membership upgraded.

Eric, please note that -- though there's no easy way to lower CYA -- there is an easy way to adjust to high CYA levels.

1. Read the Best Guess and Test Kit pages linked in my signature block.

2. Get a K2006 test kit, and find out what your *actual* CYA level is.

3. Use bleach or cal hypo to operate your pool at the appropriate chlorine level.

Points to remember:

=> "Chlorine lock" is a WAG explanation, generated by pool industry types who do not understand the CYA / chlorine relationship.
=> Test strips are horrendously inaccurate at measuring CYA levels, regardless of how you read those strips.
=> High CYA *plus* high chlorine allows you to 'store in reserve' a LOT of chlorine. With CYA levels > 150ppm, you can operate your pool by raising levels to 20 ppm or so, and then letting them coast down over a week's time.