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Swimming Pool Filters

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  • 25-02-2019
Swimming Pool Filters

Proper pool maintenance is essential to keep the pool clean and sparkling. One of the best ways to ensure this is possible is by using filters. The filter is one of the basic parts of a swimming pool that helps trap dirt particles and other debris while redirecting clean water back to the pool. There are three basic filter systems available; Sand, Cartridge and DE filters. 

view of a garden swimming pool

Cartridge Filter

This is a cylindrical filter that is fitted with a pleated paper material. The pleats in the filter help maximise its surface area. This filter can trap particles and debris as tiny as 10-15 microns. When it comes to filtering, the cartridge filter is one of the most efficient, and it's very cost-effective both in maintenance and replacement. The cost of replacement usually relies on the size or surface footage of the cartridge.  


  • The cartridge filter is the easiest filter to maintain. Cleaning the filter will involve removing it, rinsing it and putting it back. 
  • Replacing the filter, which can be done once a year or once every three years, depending on the amount of dirt being filtered, is normally cheaper than for other filters. These filters are normally recommended for the residential and screen enclosed swimming pools where they offer very efficient filtering to maintain a clean pool. 

  • For the pools that have algae or water cloudiness problem, the cartridge filter can be hectic to maintain. Since the filter uses pleated paper, it can tend to clog fast when filtering the “green” water; therefore, requiring rinsing every few hours to maintain a clean pool.

Sand Filter

The sand filters normally clean the pool water by using sand to trap dirt particles and other debris. This filter will need backwashing once there is enough buildup of debris in the filter. It usually filters debris as small as 20-40 microns making it less effective than the cartridge filter. They are normally preferred for the in-ground pools as they are easy to maintain. Backwashing will only be required once every couple of weeks, and sand replacement will be done one every 3-4 years. However, the filters are normally bulky and quite heavy. 


  • The filter is best suited for a pool that is not used frequently and is chemically maintained throughout the year. 
  • It has a very easy backwashing process to help maintain cleanliness. With the multiple valves, backwashing will require only switching the valve to “backwash” and then rinsing to return the sand into position. 


  • The sand filter only filters medium to large debris as small as 20-40 microns. This means that for the pools with an algae problem or water cloudiness, it can take longer to completely clean the pool as the sand will let the algae pass back to the pool. 
  • These filters are also very heavy and quite bulky to handle and will require a lot of pressure to backwash in case there is an overwhelming amount of debris.

Diatomaceous Earth (DE) Filter

This filter has a different approach when it comes to filtering pool water. The filter combines a natural filtering material (Diatomaceous Earth) and a cartridge. The filter has grids inside that are lined with the DE powder. The powder is made of exoskeletons of small diatoms that have been mined and fossilised. The cleaning process involves backwashing similar to sand filters, with the only difference being that they require fresh DE powder to be added after cleaning. This filter is extremely effective, trapping debris as tiny as 2-5 microns. 


  • These filters can filter debris as small as 2-5 microns and have been referred to as “water polishers” in the pool industry due to this ability; making them the best filters. 
  • They are highly effective for cleaning large pools with an algae or water cloudiness problem as they can trap everything. 


  • The DE filter requires very high maintenance. The grids inside the filter will require replacements every 2-3 years. The filter can also get punctured, allowing the powder back to the pool. 
  • Although it's easy to do the replacement, the filter will need disassembling twice a year for a thorough cleaning for the dirt that backwashing won't remove. In case you need a whole new filter, the cost will exceed even that of a new cartridge filter by far.

If you are looking for professional swimming pool maintenance in the Surrey area follow the link below.