KEMFLO PP Spun Filter for Ro Purifiers - 8 Pieces Sediment ro filter is normally used in first stage of multi stage water filter system. Frequently replacing of spun/sediment filter protects ro membrane and choking of other water filters. Impurities and sediment removal water filters. These are pre filters commonly used to remove dirt, impurities, sediment, rust, slime, sand, grass and grit.