Swimming Pool Cartridge Filters 101

 There are three main swimming pool filter types that you will find in just about every region of the World. A pool will have either a D.E. Filter, a Cartridge Filter, or a Sand Filter. Depending on your region one of these three filter types will be the most common. It’s no secret that I prefer cartridge filters and there are many good qualities of this filter type with a couple of drawbacks as well.

D.E. Filters are the most common filter type. D.E. Filters or Diatomaceous Earth Filters offer the best filtration of the three types. They use a set of grids or cloth cartridges depending on the filter type and a coating of D.E. Powder (Diatomaceous Earth). The D.E. coats the grids and acts as a barrier trapping dirt, debris, algae, and organic particles. This allows a D.E. Filter to filter down to an amazingly low 3 microns. A cartridge filter can filter down to 10-20 microns so a D.E. Filter although superior but not by a real measurable level as far as the eye can tell.

A little about what a micron is for you:

A "micron" is an abbreviated term for "micrometer", or a millionth of a meter (1/1,000,000 meters). This is about .00004 inches. For Size comparison, a human red blood cell is about 5 microns across. A human hair is about 75 microns across (depending on the person). A micron is very small measurement and a D.E. Filter will give you the best water quality of the three filter types.

Cartridge Filters the Good

Filter down to 10-20 microns

Easy to clean – simply take the lid off, remove the cartridges and hose them off

Offer the largest filtration area in square feet of any of the filter types

Cartridge filter the Bad

No way to backwash them in between cleaning

Often the builder will install an undersized cartridge filter at the time of the build

Cartridge filter the Ugly

Does poorly in areas with very, very high dirt loads 

Nevertheless, a Cartridge Filter is an excellent choice for any size pool and in fact, they make cartridge filters as small as 20 sq ft up to 500+ sq ft. They are excellent at filtering the water and will filter down to as low as 10-20 microns. Cartridge filters are a cloth-like material and the dirt, algae, and particles will stick to the cartridge and allow clean water to flow through. Much like any cartridge filter that you use for water purification in your home. The larger sq ft. of filtration area increases the flow of water to your pool and you will notice a big difference if you are upgrading your D.E. or sand filter. The pool return jets will have significantly increased power as the larger filter allows better flow.

The benefit of a cartridge filters is that they are easy to clean. Simply remove the cartridge and hose it off. The downside of this is that you cannot backwash a Cartridge Filter so when it gets dirty you need to take it apart and clean it. So figure that depending on the size of the Cartridge Filter you will be taking it apart and cleaning it every month for the single cartridge filter type to every 4-6 months for the larger 4-quad filter type.

I suggest going with a larger Cartridge Filter on your pool to save time in between cleaning and to provide the best water quality.  So for a 15,000-gallon pool, I suggest a 300 sq ft filter, for a 20,000-gallon pool a 400 sq ft filter, and for a 30,000-gallon pool a 500 sq ft filter. You can use a smaller filter if you choose, just note that you will be cleaning it often and the water flow may not be as efficient as going with a larger filter.

I think the benefit of the ease of cleaning, the large square feet filter sizes, and the increased flow to your pool all make a cartridge filter the better choice. 

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