[Hound Dog Mom]

Pool grade and feed grade DE both come from the same source, the difference is in the processing. Food grade DE is mined, dried, ground, sifted and bagged. Swimming pool DE is heat-treated (calcined), partially melted, and chemically treated. For this reason, pool grade DE contains a high levels of hazardous crystalline silica. Pool grade DE may also contain toxic levels of heavy metals. Pool grade DE shouldn’t be used for anything except filtration.