Just moved in to a 1973 house with a pool. What is the best chlorine to use? I have been using Clorox concentrate(1 gallon to 30k H2O) with positive results but it only last a day or so. I get to 4 ppm today but tomorrow it will be 1 ppm again. Is it necessary to add clorox everyday? Should I use some other chlorine? I am also adding acid (3 pints to 30k H2O) to bring Ph down about once a week. The pool was resurfaced/repaired last winter.