Apr 16, 2019· 3 Best Pool Filter on the Market. Best InGround Pool Filter Systems. Hayward S270T Pro Series 27Inch Pool Sand Filter for Inground Pool; Pentair 160301 Clean Clear Plus Fiberglass Reinforced Polypropylene Tank Cartridge Pool Filter 420 Square Feet; Hayward C5030 525 Square Foot SwimClear Cartridge Filter