I'm stumped here and looking for input.
June 4 Test Results:
FC 3.0 (yes - low for my CYA - but never got below that and that was the only time I have been below min)
June 18 Test Results:
CC 0.5 (just barely pink)
CYA 20 (This one has me stumped)
I'd been having some unusually high FC demand on the order of 8 ppm per day. No significant overnight loss so I don't believe it was an algae issue. Did a CYA test (twice) just now and ended up with 20 and less than 20.
Initially, I thought I must have a leak and I've lost a bunch of water and it had been replaced with fill water thru the auto filler.
So I ran some tests on my fill water:
CH 125 or 150
I've had no unusual acid demand or pH rise. In fact, the cup of MA I added this morning was the first I've added in over a week. If over half my water had been replaced (enough to lower my CYA from 50 to 20) my TA would be higher and my CH would have been significantly reduced? I guess that is a statement looking for agreement.
We got this pool about a year ago and it came with a CYA in the 70-80 range. I'd lowered it with back washing and splash out to the 50 and was going to ride that throughout the summer. But this high FC demand led me to discover that my CYA is disappearing.
What does anyone/everyone think? I'm going to start a bucket test tonight just to see if I find any leaking. Should start adding CYA back in and see if it stays?