Who decided the best CYA level is 30-40?


Well-known member
Aug 25, 2017
Mt Juliet, Tn
Two seasons ago I was using pucks and my CYA got up over 100. Last season I used 10% chlorine (no pucks) and kept track of all the numbers as the CYA slowly came down from rain/backwash/adding water. This season my CYA is finally in the range of 35-40. What I have found out is at the 35-40 range I am having to put in 128oz of 10% bleach to keep things above 2 FC. When my CYA was in the 50-60 range I only needed to put in 64-80oz a to keep it above 4/5. It seems like a higher CYA will cost me less money. It is also possible that my CYA test is way off but I have taken it multiple times.


LifeTime Supporter
Aug 19, 2014
Pacific NW
It can depend on sun exposure for sure. I get more than enough that cya of 30 is just wastefull.
I did find that CYA 50 works best for my exposure.