... or was the in-store test *that* far off?
on 8/27/09 I took a water sample to the pool store and got good results:
I still had tablets in a floating dispenser at the time and have switched to liquid chlorine. I got my K-2006 last Friday and have been getting CYA results of 100?!
FC 1 (added more bleach this morning to boost it back up)
I know my CYA is higher than it ought to be b/c I'm adding chlorine daily (example: on 9/5/09 I added 1 gallon of 10% bleach - about an hour after the addition my FC was up to 5, by the following morning it was down to 2.5 and by the following afternoon it was hardly detectable... I've also got a bit of a mustard algae issue that I'm keeping in check by brushing every other day and adding more chlorine towards the minimum FC although not up to the 20+ ppm shock levels on the CYA/Chlorine chart. But is it really possible that the levels could have doubled in less than a month, or could the pool store result have been artificially low for some reason?