Diatomaceous Earth filters are the most effective type of pool filter.These filters use a fine powder or "D.E.Powder" to cover a series of grids inside the filter.The powder is very fine like baby powder and can filter a particle of 2-3 microns in size.We recommend D.E.Filters for all of our new pools and for replacement filters.D.E.Filters can hold a much larger amount of dirt and debris before backwashing is needed and D.E.Filters usually can go for about two weeks before backwashing.D.E.Filters tend to clear up a cloudy pool much faster than sand filters do.The D.E.Powder is added to the filter through the pool skimmer and it then goes through the pool pump and into the filter where it coats the grids on the inside.When you backwash a D.E.Filter, you are "blowing" the D.E.Powder off the grids and out to waste.The D.E.Powder is simply disposed of and not reused unlike sand filters.D.E.Filters should be disassembled and cleaned manually at least once per season..