Pool Tech Direct Pool Filters
The Three Basic Types of Swimming Pool Filters
Swimming Pool Cartridge Filters
Cartridge filters have been around for some time, but they seem to be gaining in popularity in many parts of the country. They consist of a tank that houses three or four cylindrical filtering elements. The filters are actually made of polyester or some other material that can provide a superfine filtering surface. The fabric catches and holds the impurities until you clean or replace the filter.
The cartridge can filter out anything down to about 5 to 10 microns in size. A grain of table salt is about 90 microns; anything below about 35 microns is invisible to the naked eye. It is important to remember that with any filter a small amount of dirt actually aids the filtering process. In most areas cartridge filters are less expensive than diatomaceous earth filters but cost more that sand filters. However cartridge filters are more popular because of the minimal maintenance involved. Some families will find it sufficient to simply hose off the cartridge filter a few times during swimming season to keep them working properly. Others may need to soak the filters in detergent or replace them. In any case, maintenance takes only a few minutes to the filtration system in top shape.
Diatomaceous Earth Pool Filters
DE Filters, these products can filter out dirt as small as 3 to 5 microns. If you opened the tank of a DE filter it would look somewhat similar to a cartridge filter. But the grids are packed with diatomaceous earth, a powder made up of billions of fossilized plankton skeletons. It is the powder that actually catches and holds the dirt.
DE Filters are usually the most expensive type, and they get your pool water cleaner than the other filters. But the necessary maintenance can be a drawback for some homeowners. Most manufactures call for backwashing to clean the filter. In backwashing, the system reverses the flow of water. The clean water cleanses the filter. The dirty water is drained from the system.
Swimming Pool Sand Filters
These filters use - you guessed it - sand filtering medium. Sand filter look like large balls and they hold hundred of pounds of pool-grade sand. Basically, water flows into the top of the filter housing and makes its way down through the sand bed where the sharp edges of the sand catch the dirt. On a micron-to-micron comparison, sand filters remove the least amount of dirt – particles as small as 20 to 25 microns. But again for a time, the dirt left behind contributes to the filtering process. Sand filters certainly are efficient enough to keep just about any pool clean.
To keep a sand filter working, depending on the size of the filter you must clean it as often as once a week during swimming season. Maintenance means backwashing where the flow of clean water is reversed back into the filter. The problem with this, however, is that backwashed water is simply wasted. A typical backwashing session can waste a few hundred gallons of water – water that must be replaced in the pool.