The filters are made of polyester or other material that can provide a superfine filtering surface. The more material used, the larger the surface area available to capture dirt or debris from the water. The fabric catches and holds the impurities until the filter can be cleaned or replaced. There 3 parts to a cartridge filter construction,end caps (made of plastic) core structure to provide strength (most often PVC) and the pleated media (most often polyester with a continuously graded fixed pore structure, these cartridges provide pre- and final filtration within the same cartridge resulting in lower overall filtration and disposal cost.
The cartridge can filter out anything down to about 5 to 10 micrometres in size. In most areas cartridge filters are less expensive than diatomaceous earth filters but cost more than sand filters. However cartridge filters are more popular because of the minimal maintenance involved. In some cases it may be 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 operational.