CYA is down. WAY down.


Gold Supporter
May 27, 2019
Houston, TX
Pool Size
Salt Water Generator
SWG Type
Hayward Aqua Rite Pro (T-15)
I think I ended the season with about 50-60 CYA. The pumps run 24/7, even in the winter (low speed) with a floating thermal cover. I "opened" the pool, meaning I pulled the cover back and cleaned the pool (cleaner stays in and was daily cleaning under the cover). I did a FULL chemical check. pH was above 8. TA 70, which is the regular value. FC was around 5. CH was down to 300 from 350 (rain - washout). Salt was down a similar ratio (2800). I did recalibrate the SWG, since it did not match the Taylor salt test. And I added a bag of salt. I put in 1/2 gallon of Hydrochloric acid. Threw in 40 lbs of salt. And jumped in myself (after heating water to 79-80F!).

CYA was way way down. I've read that CYA does degrade over time, but I was not expecting it to drop to under 30, which is the limit of the test. I could still see the dot, but it was getting toward murky. I'm guessing 20-25 ppm.

Anyway, 10 lbs of CYA on the way. I'm going to leave the CH at 300, which should be fine and maybe helpful to the SWG.
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Gold Supporter
Sounds pretty typical...Between rain washout and degradation I'm usually around 30 or just below at the start of the season. I buy my CYA in a 25 lb box (Puritech) its one of those chems that stores well. I usually go through about 8 lbs a year. Give or take. I saved the 8 pound buckets from when I was buying at the pool store and I store it in there.
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