Thank you so much for responding. Last year I did go to the BBB system, but late in August could not get algea under control. I used the HTH 3XConcentrate. We cover our pool and I was ill this winter and not taking care of it. Uncovering in the last two weeks it was black. Over a period of 2 1/2 weeks we have added maybe 9 or 10 jugs of Clorox 3 X Concentrate each the equivalent of 182 ounces of bleach which if my math is correct is about 14 gallons. The water turned gray/blue and very cloudy and there were algea stains on the walls and steps. Over that period I added approximately 40 ounces of HTH 3XConcentrate. Yes I now know after reading more thoroughly that was not good. I went out and got the test kit and the things I needed. My test kit shows ZERO Chlorine and a 7.2 ph. HELP