I wouldn't switch away from a sand filter. They are just too easy. Cartridge filters aren't bad if you live someplace arid with little organic debris (leaves, pollen, etc.) but in the northeast where you are, I'd stick with sand. Plus, cleaning cartridges is a big pain and a dirty job. I'm not the pump/filter expert around here. Let me ask someone else to give you advice on what to buy. Sit tight.