Quad D.E. Filters provide the highest water clarity of D.E. with the convenience and easy-cleaning features of a cartridge filter. Four easily accessible and removable D.E. cartridges greatly increases the filter's cleaning capacity. And, cleaning couldn't be easier. In fact, you have three options: backwash and recharge like a traditional D.E. filter, remove and rinse off the cartridges, or simply remove the lid, leave the cartridges in place, open the drain plug, and rinse.Diatomaceous earth (D.E.) filters have always been recognized for providing the cleanest pool water. And cartridge filters are popular for their convenience and easy-cleaning features. Now Pentair has found a way to bring you the best of both. The new Quad D.E. Filter features four easily accessible and removable D.E. cartridges. When water passes through these cartridges, microscopic impurities like dirt, algae, and some forms of bacteria are filtered out, giving you water that really sparkles. The four-cartridge design greatly increases the filter's internal surface area, meaning much greater cleaning capacity per cycle without an increase in canister size. And cleaning couldn't be easier. In fact, you have three options... backwash and recharge like a traditional D.E. filter, remove and rinse off the cartridges, or simply remove the lid, leave the cartridges in place, open the drain plug, and rinse.The Quad D.E. combination of diatomaceous earth (D.E.) and cartridge element convenience means better performance and superior water clarity. Because D.E. removes the tiniest of contaminants - particles as small as five microns - you can count on clean, crystal-clear water for years to come.Note: Valve is not included with the filter.