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There are three popular types of pool and spa filters. They are D.E., cartridge, and sand filters. All three types work well and choosing between them is more a matter of personal preference and prior experience. We carry all types for this reason.
When selecting a filter, remember, "Size does matter." The bigger the filter, the easier your maintenance will be.
| Above-Ground | In-Ground | |
| Cartridge Filters Cartridge Systems D.E. Filters D.E. Systems Sand Filters |
Cartridge Filters D.E. Filters Sand Filters |
Diatomaceous Earth Filters
Many pool professionals consider D.E. Filtration to be the finest, because it is capable of removing smaller particles than either sand or cartridge.
Diatomaceous Earth is a porous powder with microscopic openings, that, when magnified, look like tiny sponges. Clear water can pass through these openings, but particles, as small as one to three microns, are trapped during the first pass through the media.
All D.E. filters have internal elements that become coated with D.E. It is this ‘filter cake’ that strains dirt, dust, algae and some forms of bacteria from the water.
Similar to sand filters, when a D.E. filter becomes dirty, it is cleaned either by backwashing, or regenerating and draining the clogged D.E. to the waste line. To restore filtration, a fresh charge of D.E. is added to the filter.
Cartridge Filters
When water passes through a cartridge filter, dirt is screened out at the surface of the cartridge element. When clean, the element will trap larger particles, with finer particles being filtered out as the pores of the element become clogged by the larger debris.
The cartridge element can be removed and cleaned by pressure washing inside out with a garden hose.
High-Rate Sand Filters
Sand filters share two things in common: 1) When in the filtration mode, water always flows from top to bottom; 2) They all have some sort of lateral or underdrain with slots to hold back sand while allowing clean filtered water to pass through.
High-rate sand filters use a special filter sand, normally .45 to .55 mm (also known as pool grade #20 silica sand), because it has sharp edges that serve to separate particles, allowing filtration to take place. They operate on the basis of "depth" filtration; dirt is driven through the sand bed and trapped in the minute spaces between the particles of sand. Initially, a clean sand bed will remove larger particles, and then, as the bed starts to load up with dirt, it will remove finer particles.
Cleaning of the media, or sand, is accomplished through reversing the flow through the filter, to the waste line. This is known as backwashing.
