My pool is an above ground that is 24' x 52''. It holds about 14500 gallons and I'm using a 3/4 horsepower pump with a sand filter. I also have the CYA level at about 30. Since I learned about the Pool Forum I've used nothing but 5% bleach and Muriatic Acid to maintain the pool. Before then it seemed like I never was able to keep it adjusted properly. The more store bought chemicals I bought and used, the more I needed to use them. If I need to shock I use just add enough bleach to raise the chlorine to around 10ppm and it works. Thanks again Pool Forum.