I don't understand what's going on. This is like the total opposite of what most people experience with their pools. I seem to be unable to keep my CYA up the last six weeks or so. After riding at 70 ppm for the spring and start of summer, right after the 4th of July my CYA was at 60 ppm. I started using some tri-clor pucks to slowly rise the CYA back up and a chance to cut back on the SWCG and give it a rest for a little while.
So after two weeks of this i tested CYA again and it was down to 50 ppm. So i'm thinking that's not right, so i doubled up on the tabs for another week. Tested after that week and CYA was still at 50 ppm. So at this point i'm down to the last little bit of my flask of CYA reagent so i order a new one thinking maybe this little bit of old reagent is the problem. So after another week of waiting for the reagent to show up and still using pucks, i tested with both old and new reagents and got 40 ppm with both.
So off to the store to get some CYA. Pool math said i needed 49 oz to get back up to 70ppm. Got a 5 lbs can of dry CYA so 49 oz would be just over 1/2 of the can. So not wanting to over shoot i put 1/2 the can into skimmer sock expecting to get at least 60 ppm the next week. Low and behold the next weeks test showed 50 ppm, maybe even 55ppm. So in went the other 1/2 of the can of CYA and tomorrow i will test again.
The first thing i was thinking that my pool has more gallons than i thought. The PB did say that the pool was 16K gallons but i have checked twice now with setting up exactly how the pool was filled and how long it took to fill two 5 gallon buckets and came up with just over 12k gallons both times. I think if you took out the six foot tanning ledge then the pool would be more like 16k gallons. So i'm pretty sure it's not pool size as to why my CYA is not going up like i think it should. I know a little CYA gets splashed out and that a very little bit of it breaks down over time but not almost 30 ppm in a month to month and a half.
Anybody with ideas on why this is happening?