The most common type of material used in filter media is sand because it can effectively clear pools for years with little or no problems. It is also the most inexpensive type of filter media which makes it popular among pool owners. DE is another type of filter media that can be used for pools but it not frequently used because it requires more maintenance work. Pool builders usually suggest cartridge filters because they are maintenance friendly.
Most pool builders will ask the owners on the kind of filter that will be used. A pool owner can decide based on the level of maintenance that he is willing to perform on his pool and the long term costs. In order to make the right choice it is best to be knowledgeable on the different filters that are available.
Sand is an old technology and it is also the least expensive. If you take a look at older pools you will find them with sand filters. A special kind of sand is used by the pool industry. It filters water by moving through the tank from the top down. There should be about 75% sand and 25% free space inside the tank. As the tank fills up with water from the pool, water passes through sand that filters out all the tiny microns that it can trap. Dirt and debris will remain inside the tank until is backwashed. Sand generally has to be replaced every 3 to 5 years depending on the length of swim season and how the pool is maintained.
DE filter works in the same way as the sand filter but instead of sand, the DE filter contains a set of grids or fingers that are coated with DE powder made from crushed sea shells and external silica secretions of little microscopic sea creatures that are called diatoms. The fingers trap most of the dirt and debris at a much lower micron level than sand.
A pool builder will usually install a cartridge filter because it is maintenance friendly. In this filtration system, cartridges made from spun polyester that are pleated and wrapped around plastic PVC will trap the debris. Cartridge filters do not need to be backwashed like sand filters.