Glad to find this forum!! I've been doing my pool maintenance since I purchased it in 1998. It is a 24' in diameter above ground with a vinyl liner. The pool originally had a cartridge filter, which I changed a year ago along with the pump with a Hayward sand filter and Hayward Power Flow Matrix pump. I have had good years and I've had bad years trying to keep my pool maintained. The local pool folks around where I live have a fair amount of turnover every year so I get less than adequate help from them. I am glad I found this forum as I am looking forward to reading and learning how to actually maintain my pool properly.