We had an Intex 1500 gph sand filter & pump, (one it came with) and got rid of it and got a better Intex 2500 gph pump with a cartridge filter. Should we have stuck with the smaller pump and sand filter. Which do you prefer sand or cartridge? Friends who are pool cleaners said they don't like sand and convinced me to get cartridge. Were they right? I see many of you have sand filters. Thank you.