AquaPerl Perlite Filter Powder is a new, lightweight, direct replacement for diatomaceous earth media. A safer alternative for all D.E. filters. 1/2 lb. of Perlite is equal to 1 lb. of D.E. so you will save money using less filter media. Filters down to 3 microns. Pre-coats fast and effectively as well as reduces time spent on filter cleaning. All natural and chemically inert.