> I simultaneously siphon and fill the pool to adjust CyA down, but then have to redo alk and ph. I am not disciplined enough to go full-liquid in my sunny area, and too cheap to buy a liquid chlorinator. You probably wouldn't do that if you lived in an area that charged much for water. In our area a 1/2 drain and fill would cost me about $62. In my pool I would have to do that every few weeks to keep cyanuric acid between 30 and 60 ppm. Each puck adds 3.3 ppm cyanuric acid per 10,000 gallons. My pool is 20,000 gallons, so going from 30 ppm to 60 ppm takes about 26 pucks.