I just used 4# of calcium hypochlorite to shock my pool, as I have developed mustard algae thanks to the rain floods in Texas. I should be reading about 25 ppm of chlorine, but my Taylor test kit shows almost no chlorine! It dropped my pH from 7.8 to 7.2. Why donít I register chlorine with the test kit?
19,000 gal in-ground plaster pool; plaster older than 10 years