Surprise CYA reading--a little help, please?


LifeTime Supporter
Aug 2, 2010
Rural Moloka'i, Hawai'i
I recently had my pool covered (solar cover) for a week during a stretch of bad weather. Uncovered it a couple of days ago, of course TC was low. Ran the pump and filter as well as the SWG. At the end of the first day, I also checked CYA and the fluid in the tube was absolutely clear. Tested again. Same result. Added about a half-cup of CYA granules (I try to add in small increments because my pool is small) and tested the next day, and the day after. Added another 1/4 cup today. Still clear. I should be getting some result by now, yes? I am getting worried about overtreatment at this point.

My CYA has always been in the 50-70 range, and I'm not sure why it would drop so low over 6 days.

The only other thing that has changed is that I opened a new bottle of R-7065, the CYA test standard. Could it be a bad batch?

TC is rising, now at 3, pH is consistent at 7.8 and water is clear.

Thanks for your help and advice.



LifeTime Supporter
Mar 14, 2009
Huntsville, AL
I've had good luck using the pool calculator to determine how much CYA to add and then waiting a week before testing for it (apparently it takes that long to show up in the test).

Also, are you using the right reagent for the CYA test? Depending upon which test kit you have, I think R-0013 is used in the CYA test. The CYA test standard is used to to check your testing technique (I believe you use it in place of the pool water and you should measure CYA = 50 ppm when the test is done correctly).
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