Every Traditional Collection model comes standard with a commercial-grade filtration system. Other spa brands have skim filtration systems - which submerge the dirty spa filter in the spa water with you. Skim filtrations systems are only approved for use in private settings. Coast Spas' Hydro Cyclonic Filtration uses the same technology as systems used in public pools and hot tubs - the filter is removed from the bathing area and housed in a closed, pressurized canister.