The quick answer
Cartridge filters are simple and conserve water, DE can filter very fine particles, and sand filters are durable and easy to backwash.
Cartridge filters
Pleated elements capture debris and are removed for cleaning. They avoid routine backwashing but eventually require replacement.
DE filters
Diatomaceous earth coats grids and filters fine particles. Maintenance requires correct media handling, grid inspection and responsible disposal.
Sand filters
Water passes through filter media and cleaning commonly uses backwashing. They use pool water during backwash.
Compare total ownership
Consider equipment price, replacement media, water use, space, valves and service time—not only filtration fineness.
Maintenance matters most
Any filter performs poorly when flow is restricted, parts are damaged or cleaning is neglected. Proper sizing is essential.