High CYA

[geneqo]

Does CYA deteriorate during the summer or is the only way to lower it is by dilution?

[aylad]

It does not deteriorate during the summer--if you lose any during summer, it's usually due to splashout, backwashes, leaks, etc. Draining and refilling water is the only REAL way to lower it.

It does occasionally deteriorate during the winter, in pools that are allowed to go swampy, but in those cases, the byproducts create huge chlorine demands on opening, so that's not a good option!!

Welcome to the forum!

[Watermom]

It does occasionally deteriorate during the winter, in pools that are allowed to go swampy......

And, sometimes even in pools that do not go swampy.

[PoolDoc]

Janet, Watermom;

The degradation of CYA to ammonia is 1 of 3 possible routes. It can also go to nitrogen gas (no problem) or nitrates (no immediate problem), and in my own experience, one of those two is the most common. I assume that the weather this winter somehow is related the very high frequency of the CYA=>NH3 events, but I don't really know.