CYA effectiveness/breakdown in hot water?

[Kjac081]

I recently got my latest bull order of CYA; I decided to by 50# from Doheny’s. It’s 100% cya per the label, but doesn’t seem to be making an impact on cya levels like other brands have. Im not sure if this is somehow a knock off, but also read that high water temps can degrade cya. Water temp south of Houston is 92-94° lately

Last week my CYA measured about 55, so I added about 3 1/2 # per the Pool Math app (which is usually always). 4 days later and still testing about 60.

 

[needsajet]

Nice to meet you via TFP.

We talk about CYA in increments of 10 partly because of the test's inherent inaccuracy. Your CYA product is probably fine, although I'd reserve judgment through another addition and test to see how that goes. CYA of 60 gives you heaps of protection, so there's no immediate urgency to go to 70. I like to test a week after an addition, and buy the cheapest CYA I can find, without regret.

I've made the mistake of cleaning my filter, but I'm guessing that's not a factor here.

Per the effectiveness aspect of your question, CYA remains effective across pool operating temperatures, including spas.