Diatomaceous Earth (D.E.) filters have the highest filtration capability out of the three pool and spa filter types available. They are capable of filtering down to 3 - 5 microns. This provides better water clarity when compared to cartridge and sand filters. D.E. filters require backwashing. Backwashing is reversing the flow of water to remove the debris stuck in the filter media. When the pressure in the filter increases 8 - 10 PSI above the starting pressure, backwash the filter 3 - 5 minutes or until the water runs clear from the backwash line. D.E. filters should be backwashed every 6 months depending on debris levels. They should also be disassembled and cleaned once a season to remove any caked D.E. powder. It’s recommended to replace your grids every 4 - 6 years depending on use. Here at PoolSupplyWorld, we offer all the most reliable and popular manufacturers and brands such as Hayward, Waterway, Pentair, and many more! If you have any questions or concerns please feel free to contact us at 1-800-772-0467 or chat with us online at www.poolsupplyworld.com.