How does a DE filter work on a pool?

Simply put, Diatomaceous Earth (DE) are the bones of tiny little animals that lived millions and millions of years ago, diatoms. This DE is used to coat the "grids" inside the DE filter which captures and filters particles as small as 5 microns. When the filter pressure rises, the swimming pool DE filter is backwashed in the same manner as a sand filter. A slurry of DE is put into the skimmer to "recharge" or "re-coat" the grids of these swimming pool DE filters. This type of filter is effective and efficient but a little more expensive to maintain. Some call it the "water polisher" of pool filters.