Diatomaceous Earth (D.E.) is proven to be the most effectivefiltering medium for removing microscopic particles as small as5 microns (which are invisible to the naked eye). With its manypores and sharp corners, D.E. does a superb job of trappingthis tiny dirt and debris. Thanks to its design, the EasyCleanautomatic regeneration filter makes it even easier to enjoy theadded water clarity that only D.E. media can deliver. It's thesimple, trouble-free and highly effective filter.