There are basically 3 types of swimming pool filter: Sand Filter, Cartridge Filter and Diatomaceous Earth Filters (DE Filters for short)
There are a few other types, but i will will explain these 3 as they are the ones most commonly used.
Sand Filter
Sand filters use a specially graded sand as the filter media. The water enters the top of the filter via the manifold (most commonly a multi-port valve).
The water is then distrabuted evenly over the filter media, the water radiates through the media, removing most solids, then the water reaches the collection sytem and passes on through the filtration cycle.
Sand filters filter out debris down to about 40 microns in size. Anything smaller than 40 microns will probably not be filtered out.
Diatomaceous Earth Filters (DE Filters for short)
DE filters use diatomaceous earth as a filter media. The DE filter has plastic grids covered with a plastic type of fabric. A layer of filter powder called Diatomaceous Earth covers the grids and does the filtering.
As the water passes through the filter powder, any debris down to 5-8 microns is filtered out. Because the DE is much finer that sand, it is able to filter much more finely than a sand filter.
Cartridge Filter
This type of filter i would say is the simplest type, it mainly consists of a tube with pleated strips that collect the debris. These type of filter had a bad reputation as they were in need of constant cleaning. Today are are much more affective and require much less cleaning. They are mainly used today for Spas and Hot Tubs.
Related articles
How a swimming pool works
How we get water
Types of swimming pools
How swimming pool pump works
Related articles