Does winter (midwest) impact CYA levels?

[chem geek]

My pool is in-ground, but it is true that I dilute it with winter rains and that lowers the CYA level, but I've accounted for that. What I don't understand are the reports of people losing virtually all of their CYA over the winter when they aren't doing a drain/refill. You are right that some people may be doing a partial drain/refill to get below the skimmer in cold climates (it doesn't snow where I live near San Francisco and only sometimes gets to freezing -- the pool water never freezes) and that would lower CYA levels, but people are reporting all of their CYA going away even when they start out with high levels.

I will keep better track of my CYA levels now through next year's summer season and perhaps there is a normal but slow degradation of CYA that occurs and that, for reasons I can't explain (yet), it's either more noticeable over the winter or occurs much more rapidly over the winter. The anaerobic bacteria explanation is real as some of them do consume CYA, but I just don't like the idea of having such bacteria survive in a chlorinated pool.

For now, I'm boosting up my CYA level (since it's nearly gone) and will see what happens over the winter and next summer.

Richard

[NWMNMom]

keep us updated on your findings - is it possible there are "super bacteria" thriving in chlorinated pool environments? Sounds scary but anything is possible these days, especially with the contaminants in our rain/snow......