Product Information:Hayward's StarClear Plus filters offer added quality, value and convenience in cartridge filtration. StarClear Plus filters the ideal choice for the most demanding applications and environmental conditions. Plus, with a larger filtration element, StarClear Plus filters have greater effective filtration a than similar sized and priced cartridge filters.How A Cartridge Filter WorksSingle Locking Knob securely fastens filter head to filter tank, eliminating clamps or bolts. Filter Head provides easy access to cartridge element. May be rotated to conveniently position pressure gauge and manual air relief valve. The HeavyDuty Filter Tank injection is molded of reinforced thermoplastic for dependable, corrosionfree performance. Scavenger Tube Air Relief purges any trapped air during filter operation. Single Element Cartridge is engineered of highquality reinforced polyester, with gasketed molded end caps, for maximum efficiency, easier cleaning and longer life. PrecisionEngineered Extruded Core provides extra strength and superior flow. Elevated Filtered Water Collector and Debris Sump prevents accidental byp of heavy debris to pool or spa when cartridge is removed for cleaning.See below to read the differences between D.E. and Cartridge filters.D.E. vs Cartridge Filters: DE is always a much better filter; it will filter about 10 times finer particles than cartridge will. Cartridge filters need to be cleaned every few months, whereas DE filters can usually go month or two longer for similar sized filters. Backwashing is not recommended, but you want to you can. If a DE filter is properly sized (48 or 60 sq ft for most residential pools) they will usually only need to be cleaned 2 times a year. Without the help of cellulose, a cartridge filter will have a very difficult time filtering out algae (should the pool get it which all pools do),when you add one of these products it's basically like putting DE in a cartridge filter.