All of my numbers appear to be okay on my test strip and oto test kit but I have dead algea(white) and green algea so bad that you cant see over a foot in my 26 foot X 52 inch round pool. I have cartridge filter. I wonder if sand would work better or faster in filtering my pool. This is my 4th year fighting algea!!! Last year, the ONLY way for me to rid my pool of algea was to floc almost every other day. Its like my filter will have nothing to do with algea! Any reply is already greatly appreciated. Best regards,Barry.