Hi. I am at a loss, i am ready to just throw in the towel with my pool. I am having much difficulty maintaining the 20ppm for more than a day. Once I get to 20ppm at dusk I re-check in the morning before leaving work at 7am and it drops a little to 19ppm. I add a little more, and then re-check when I get home from work at 5pm and it drops down to 13ppm. I add more bleach to get back up to 20ppm. I have been doing this consistent and get same results. It's been really hot here in NC which is burning the chlorine quite quickly and I am spending so much money on chlorine at $3+ per gallon. Each 121oz. liquid bleach is only giving me about 1.3 ppm and that is the generic brand from target and walmart, 8.25%. Any other suggestions?? Thank you.