Quote Originally Posted by VOLDADDY
2nd, my CYA dropped from 40 to around 25 in less than 2 weeks. I will add to bring back to about 40. Would a constant barrage of bleach 2-3x daily dilute the CYA?

Thanks.
No, the bleach would not have any impact on the CYA levels, BUT you are showing symptoms of what I've suspected: something is biodegrading your CYA. I was kinda wondering if your CYA levels had dropped mysteriously recently. If I remember correctly, you did add some CYA, and that may have covered the fact that some of it had been degraded.

This biodegradation is primarily anaerobic, and produces ammonia as a result of the breakdown. This creates a prodigious Cl demand, much like what you have experienced.

The one thing that puzzles me is that your CYA seems to have dropped while you were beating away at it with large doses of Cl. I'd think that whatever it was would have been nuked by those high Cl levels. This is why that kind of CYA degradation usually happens over the winter in uncirculated, low Cl pools. It's highly unusual for this to happen in a operating pool, unless you have some secret dead spot somewhere....

Michael