Minerals DE Swimming Pool Filter Media-50 Pounds, 3-5 microns in Size, White

DE is added to your pool filter by volume (typically 1 lb plastic measuring cup). Since DE is sold by weight, I recommend Dicalite DE as it is significantly drier than the plastic-bagged DE sold locally. In other words, I get more cups of DE from a 50 lb bag of Dicalite than the 50 lb bag of wet/damp DE. Pricing from Amazon is excellent and delivery is only a couple of days.