I thought I had it..

[rdkll]

I may be assuming too much by the math, but my cya was about 90...so I dumped appx 6700 gal ( 896 cubic feet) of water and it shoud have dropped it appx 20 points to 70......shocked at 15ppm until zero loss overnight. Then I was maintaining appx 10ppm and when I check it again at the end of the day it was down to 1ppm early this evening..

I am waiting till I get my refills to check cya again.......

 

[dmanb2b]

hmmm...any chance kids or someone had a "accident" in the pool?....even if your CYA went down to 30, you should not have lost that much FC in one day. Any chance you have a recent CC measurement?