Diatomite Procedures for Coating Pool Filters

Diatom

• The name Diatomaceous, or diatomite, comes from the word diatom. A diatom consists of a type of algae that flourished approximately 15 million years ago. The fossils of diatoms, found in abundance in some soils, contain microscopic holes. When used as a filtering device, these holes allow water to pass through them while trapping particles as small as 3 microns, or about 0.000117 inches -- the size of an average speck of dust. Diatoms are small enough that they combine with soil to form a dirt-like substance known as Diatomaceous earth.

Diatomite Filters

• Diatomite filters consist of above-ground systems with a pump, large filtering container and a series of pipes. One of these pipes brings water into the filter from the pool, while another set takes water out of the filter and puts it back in the pool. Yet another pipe connects to local waste water systems. The pump powers all water movement. For a DE filter to work properly, you must coat the actual filters within the system with Diatomaceous earth. Technically speaking, you can coat any filter with Diatomaceous earth simply by rubbing it onto the filter, though this may not actually work as a filtering system.

Filter Coating

• The process of coating a diatomite filter in Diatomaceous earth requires minimal work on your part as a homeowner. You simply need to introduce raw Diatomaceous earth, purchased at a pool supply outlet or from a manufacturer, into the water flow entering your DE filtration system. Do this by adding the Diatomaceous earth to the system's skimmer. When the water flowing through the skimmer reaches the filters the Diatomaceous earth becomes stuck on, and coats, these filters. Filtration begins working right away upon application of the coating.

Backwashing

• Backwashing entails the process of cleaning out a pool filter by pumping dirty water collected in the filter out of the filtration system and into a waste water system. When you backwash a diatomite filter, the waste water passes through the filter in a reverse direction on its way out of the system and takes Diatomaceous earth with it. Therefore, you must re-coat the filter with each backwashing. Online pool supply store Clean Pool and Spa recommends bachwashing a DE filter every four weeks. Roberts Hot Tubs, an installation and maintenance company, meanwhile, points out that some towns or counties maintain very strict regulations about Diatomaceous earth disposal, meaning you must clean filters to remove the coating before bachwashing. Check local laws for more information.