Hi all, within a day or two of adding a gallon of liquid chlorine to my pool my reading is back at zero. Took a sample to my local pool shop and they said everything looks good except for the low chlorine level. They said a gallon a week should be sufficient for my in-ground 19,000 gallon pool. Because the pool was painted, my pool guy suggested not using tablets and only using liquid chlorine. What could be causing the low reading? Should I maybe add half a gallon twice a week instead of the full gallon at one time? The water is clear and the pool appears clean.