Diatomaceous earth, or DE filters, incorporates the exoskeletons of tiny diatoms to efficiently filter your swimming pool water. The exoskeletons coat the filter’s grid housing and act as a sieve to remove particulate. Ultimately, DE filters have the lowest micron rating out of the three different types of filters at about two to five microns, and are known as “water polishers.” Diatomaceous earth filters are typically the most popular choice in swimming pool filters when it comes to removing the smallest particles. DE filters could be the right choice for you if you want perfectly filtered water.Although these pool filters can efficiently remove fine, small particles, they actually require a bit more maintenance than other pool filters. They typically run at a high pressure, and must be backwashed once they need to be cleaned. Backwash refers to running the water backwards through the filter to remove trapped dirt and debris within the media after the pressure has dropped.