My above ground pool is roughly about 26000 gallons. I have both a sand filter and a 150 sq foot cartridge filter. I run a poolskim and zeolite on the sand filter in place of sand. I love the sand filters ability for easy maintenance and back washing capability. It's a salt water pool so I have an aquarite hooked up to the sand filter on a timer. I like to have a filter running 24x7 and this is what I use the cartridge filter for. I utilize two speed pool pumps so I can let the cartridge filter run on low speed without having to exhaust the hours on the aquarite cell. Pool stays crystal clear. Cartridge filter maintenance is a little more work in that the cartridge has to be removed, hosed down, soaked in cleaner (dishwasher detergent) rinsed and placed back into service. Cartridge replacement times will vary but the filter also picks up smaller debris.