Cartridge filters vs sand filters: Cartridge wins for small pools under 15,000 gallons

Cartridge filters are simpler and waste no water — just rinse with a hose every few weeks. Sand filters need backwashing that dumps water down the drain, which is overkill for a small pool. Cartridges also filter finer particles (10–15 microns vs sand’s 20–40) for clearer water. The trade-off is replacing cartridges once a season for $30–60, but that beats dealing with backwash valves and replacing sand every few years.