Diatomaceous Earth (D.E.) Filters can be metal, fiberglass or plastic just as all other filters. Water is pushed through a D.E. filter, just as any other filter. The pump pushes the water into the filter past a series of 8 D.E. filter grids. These grids have a plastic skeleton and are coated in a fine screen-like mesh material. This material is made to hold a filter media called Diatomaceous Earth (D.E.) which is also commonly called filter powder. It is a very fine powder, much like baby powder. The filter grid’s job is to hold the powder, while water is pushed through and inside the filter grids and then returned to the pool. Any dirt and debris is held by the D.E. powder while the clean and filtered water is returned to the swimming pool.
What is diatomaceous earth?
Diatomaceous earth, also known as DE, TSS, diatomite, diahydro, kieselguhr, kieselgur or celite) is a naturally occurring, soft, chalk-like sedimentary rock that is easily crumbled into a fine white to off-white powder. This powder has an abrasive feel, similar to pumice powder, and is very light, due to its high porosity. The typical chemical composition of diatomaceous earth is 86% silica, 5% sodium, 3% magnesium and 2% iron.
Diatomaceous earth consists of fossilized remains of diatoms, a type of hard-shelled algae. It is used as a filtration aid, as a mild abrasive, as a mechanical insecticide, as an absorbent for liquids, as cat litter, as an activator in blood clotting studies, and as a component of dynamite. As it is also heat-resistant, it can be used as a thermal insulator.
Cartridge filters are very similar in function, shape and size to D.E. filters. Often a manufacturer will use the same body of a D.E. filter and only change the insides to hold a cartridge or several cartridges rather than D.E. filter grids. Cartridge filters operate in a similar manner as D.E. filters in that the pump pushes water through them, however the difference is in that rather than having grids to hold D.E. powder, within the filter is a large cartridge or a series of smaller cartridges that hold dirt and debris. Most commonly 4 cartridges are inside filters in our area.
These cartridges require no additional media to filter, as a D.E. filter does(D.E. powder), and cleaning them is quite simple. Cartridge filters do not backwash as a D.E. filter does and they don’t have a multiport valve. To clean a cartridge filter when it gets filled with dirt and debris and the filter pressure rises you merely have to remove the cartridges from inside the filter and hose them off with a garden hose or cartridge cleaning tool that was explained in the first section of this handbook. This cleans the dirt and debris from the cartridge making it clean and ready for use again.
Sand filters are commonly used for residential but even more commonly for commercial swimming pools in VA, MD or DC. Sand filters, in function work similarly to D.E. filters in that they can be backwashed, have backwash valves and should be backwashed about once per week. Sand filters are mostly if not always plastic or fiberglass.
When you are backwashing a sand filter, allow it to backwash for a couple of minutes, more so than you would with a D.E. filter. There is no powder or other filter media to add to a sand filter.
Inside a sand filter is a large compartment that holds fine sand. The water is pushed through this sand and the clean water is returned to the pool. The sand in this inner compartment collects the dirt and debris and serves as the filter media. Backwashing a sand filter once a week will blow much of this dirt and debris out of the sand and send it to the backwash line, just as it would with a D.E. filter.
Once every 3-5 years the sand inside a sand filter should be removed and replaced with new sand.
