First, thanks to all of the smart posters sharing their knowledge...I've been lurking for a few days as I've gone through pool green water ****, and I think thanks to various posts I know what I am dealing with....
I have not gotten my own home test kit, but I have taken multiple samples to two different pool stores and am now pretty confident my CYA is out of whack, hence the green pool water and high chlorine bill doing NOTHING to fix it. All of my other readings...alk, dissolved solids, FC, PH, ect..all in the good to high end ok of Pool School readings.
First CYA test came back at 100 a week ago. I found your site, and became suspicious that was my issue. Next I had a reading done at a different pool company test, 50/50 distilled to pool water...THAT reading showed 200. To verify I was FINALLY at the top end of my CYA reading, I made my own 25% pool water to 75% distilled mix at home, ran to another pool store and had them run the test...it showed CYA around 40....So I think(???) my reading of 200 is pretty accurate.
My question to the smart folks here is simply...think I would be good with HALF refill of my 24,000 pool....or maybe like 2/3's? I live in a desert area, water is precious, so I will do what I need to do, but I'd like to waste as little as possible.
Thanks for reading this