Choosing A Filter System

It is important to have a good filtration system. Pool water is cleansed by passing water through a filter, then trapping and removing suspended particles in the filter media.  Failure to remove suspended matter can result in unhealthy and unsafe water, and increase your chlorine consumption.

There are 3 types of filtration systems:

  • Sand
  • Cartridge
  • D.E. (Diatomaceous Earth)


Sand and Cartridge are the two most popular, and DE is the least.

Each filter system catches debris at different Microns. As a reference, Table Salt is 100 microns, and human hair is 70 microns.  A sand filter, filters down to 50 microns. A Cartridge filter, filters down to 15 microns, and DE down to 4 microns.

Although DE filters down to the smallest micron of all three filtration systems, DE is rarely used, and for a good reason!  DE powder is so fine; it is easily to go airborne. If improperly stored, which is easy to do, or improperly disposed of, it can cause silicosis, a fatal lung disease.  DE is a known carcinogenic and must be disposed of in a manner compliant with local codes. It can also get trapped in the mechanics of your pump or equipment, causing it to fail prematurely.  But if used properly, it is the Best filtration system.

Cartridge filters are what we recommend most here at Viscount Pools of Metro Detroit.  We like them most for a few reasons. Cartridge filters are very compact in size, they are a lot smaller compared to Sand and DE filters. Cartridge filters do not require backwashing, so you conserve water. Cartridge filters also filter down to a smaller micron most safely. Cartridge filters only need to be replaced about every 4 years, and can be easily cleaned, by either a quick rinse or good soak in a filter degreaser over night. Cartridges, rarely need cleaning throughout the swimming season if the pool is properly maintained.

At Viscount Pools of Metro Detroit, most pools that we sell, come with a 2-speed pump and cartridge filter system. Cartridge filters work very well with 2 speed systems. With a variable speed pump, you can set your pump on low speed and allow it to run 24/7. This is more energy efficient than a high speed pump and puts less wear on a pump that is constantly being turned off mid speed. You are also turning over your pool water more frequently, resulting in less dead spots, and catching more small particles. With the water constantly moving, algae is unable to form. With a one speed (high speed) pump we recommend filtering anywhere from 8 – 12 hours a day. The longer you allow your water to filter, the more sparkling your water will look. Which looks cleaner; a Stagnant Pond or a Babbling Brook? 

Sand filtration is the oldest type of filtration.  As the water filters through, debris gets caught between the sand particles. As the filter cycle continues, progressively it filters smaller particles. A general rule of thumb with Sand Filters is when vacuuming algae, vacuum straight to waste.

A common rule for Sand is it needs to be replaced every 4 – 7 years.  This is rule is good for aquatic facilities that are indoor, or pools in the Southern States that are capable of running year round. Pools in Michigan generally close in August, and are opened around the end of May. This sand sits in the warmth, and organics form in the sand particles. By the time you open your pool, and use the same sand, you will notice that you may consume more chlorine and fight with algae. Here at Viscount Pools of Metro Detroit we prefer not playing the guessing game with sand. At $11 a bag, we suggest replacing the sand every year.

Cleaning a Sand filter is easy. It’s important to backwash a sand filter when the pressure increases 8 – 10 psi over the starting pressure. During backwash, unfiltered water passes through the sand, and shoots out the waste port until the waste water looks clear through the sight glass. You will lose water.  Although most people do not like replacing water, not all water loss is bad. It’s important to control the amount of undesired solids building up in the water.

A newer product that has been becoming more popular is Zeolite.  Zeolite can be used in some sand filter systems and filters down to 5 microns. Some use this in conjunction with sand, but it is important to speak with the filter manufacturer before using so you can specify whether it is compatible with the filter system and warranties.  This has an exceptionally high surface area, and if used improperly or against manufacturer instructions, can increase the pressure in filter more than recommended.

If you are having a hard time deciding which filter system is best for you, please feel free to talk to one of our knowledgeable Pool and Spa Professionals. 



36568 Groesbeck, Clinton Twp MI 48035     (586) 792-4920

27795 23 Mile Rd., Chesterfield MI 48051     (586) 948-8717


“Like” Us On Facebook: Viscount Pools of Metro Detroit

No Comments