Choosing the right filtration system for your pool not only benefits your family’s health but can also prevent general damage to your swimming pool. Filtration systems force pool water through certain types of porous materials to clarify and clean water of organic and inorganic particles. Unless you have some kind of pool filtration system to optimize water quality, you could be battling recurring algae growth, bacterial infections and accelerated deterioration of your pool.

The commercial pool industry recommends using one of three filtration types available: DE, cartridge and sand. But what’s the difference among pool filtration systems and which one should you use?

Diatomaceous Earth (DE) Filtration System

Diatomaceous earth is silica-based, filtration material composed of crumbled, sedimentary rock containing fossilized organisms called diatoms. Of the 3 filtration types, D.E. is clearly the best and will filter down to 2-micron sized particles when operated properly.  Sold as a fine powder that is slightly abrasive, DE efficiently absorbs and filters impurities and microscopic contaminants from swimming pool water.

This type of filtration works by using what is called an element that is wrapped in a porous polypropylene fabric.  You then coat the element with the D.E. powder evenly around the entire element or element assembly.  The D.E. then catches the biologicals and particulates and allows clean water to pass through.  Eventually, the D.E. will saturate and need to be discarded of and replaced.  This type of filtration is the least forgiving of all three types and requires close attention be paid to the cleaning procedures.

DE meant for pool filtration has been calcinated (heat treated) to convert the molecular structure of silica. The new structure significantly improves the ability of DE to filter microorganisms and pathogens. If you decide to install a DE filtration system to clean your pool, be aware that food grade diatomaceous earth should not be used in swimming pool filters. Food-grade DE hasn’t been calcinated and won’t provide maximum filtering abilities like pool-grade DE.

Sand Filtration Systems

This filtration type falls under a broader category of permanent media filters.  It is classified as a “sand filter” when sand is used as the media of a permanent media filter.  These types of filters typically work by bedding the media to a manufacture specified depth above the laterals at the bottom.  Water will flow into the top of the vessel and simply go through the media into the laterals and back out to your body of water.

When utilizing regular filtration sand in a permanent media filter, this would be worst of the three in size of particulates filtered and typically lands in the 20-40-micron range.  That being said, there have been many

improvements in this industry and CPI now offers an NSF listed glass media that has been tested to remove particles down to 5 microns.  This glass media is much less susceptible to other issues with sand filtration like tunneling or calcifying/hardening.

A large advantage to permanent media filters is the cleaning procedure called backwashing.  To do this, you typically just reverse flow for a period of time or until you see the water clears up.  With a very forgiving cleaning process that is easily automated, this is probably the most popular filtration type nationwide.

Cartridge Filtration Systems

Cylindrical in shape and containing pleated filter material, a cartridge filtration system can remove contaminants 10 to 15 microns in size from pool water. Although sand filters can also

capture microscopic debris, cartridge filters are the easiest to maintain compared to DE and sand filtration. Pool owners using a cartridge filter typically need to replace the filter once a year. The size (square feet) of a cartridge determines how much it costs.

Advantages of using a cartridge filtration system include its low maintenance, affordability and capacity to maintain water clarity. Compared to D.E. and Sand filtration, cartridge filtration less prone to operator errors that could result in actual loss of filtration.  It would require an actual rupture in the cartridge to have bypass where as D.E. and sand filters can have bypass with tunneling or improper D.E. coating and precoating procedures.  This is why this filtration is the preferred filtration type for spas which are extremely small bodies of water that can be contaminated very easily.  Improper cleaning of the cartridges will lead to shorter filter runs but won’t result in loss of filtration.

In summary:

  • D.E. filtration will filter the most particulates out but requires a higher-level operational knowledge to function properly.
  • Permanent media filtration has made large strides in reducing particulate sizes able to be filtered out.  Also, is operationally friendly and easy to automate.
  • Cartridge Filters continue to be a solid filtration method with little operational knowledge needed to maintain.  Improper maintenance does not result in filter bypass so is a safe selection especially for smaller bodies of water.

For over 40 years, Com-Pac Filters has been helping pool owners select the right filtration systems and pool pumps for their commercial swimming pools. Don’t take a chance with the expense and stress of dealing with cloudy, dirty, contaminated water. Contact us today for immediate assistance with purchasing the best filtration system for your pool.