Watermom: I was thinking the same thing. I have a 5 lb bucket of CYA, so I may add a little at a time and try and bring it up. Bleachcalc says to use 2lbs 6oz to raise 10ppm, so I'll probably put a pound in, wait a week and test again. We haven't had a lot of warm sunny days yet, so the Cl level has been pretty stable.