Filters – How Do They Work

Okay, after a few weeks hiatus we are back to the filters…..

Filters — How Do They Work?

First, there are three kinds of filters available on the market these days – sand, cartridge and DE.  Sand filters work by moving the water into the filter and pressing it through the sand. The sand is the mechanism which catches and detains the offending microns.  These filters tend to be larger than other filters.  They filter up to 20-100 microns, which means your sand filter friend spewed some particles back into your pool water.  Sigh.  He may be the most popular filter out there, but he certainly isn’t the most effective. Cartridge filters function by moving the water through the filter medium, which can range from a pleated fiberglass mat or a sort of synthetic fiber (never paper!).  Cartridge filters come in two different qualities – one being “disposable” and the other lasting much longer. You’ll find that cartridge filters do filter in the 10-15 microns range, meaning that fewer offending particles are getting back into your pool water.  But, don’t shout hurray yet.  In terms of effectiveness, there’s one more filter type worth noting.  The DE filter uses a grid coated with nylon material.  Diatomaceous earth is dumped into the filter and clings to the nylon material.  This widely available and inexpensive powder known as “DE” is really tiny diatoms or exoskeletons which were fossilized and then mined from the ground. The DE that coated the nylon material covered grids acts like tiny sieves, laboring on your behalf.  In essence, the delicate powder is really the most effective filter on the market, filtering in the 2-5 micron range.  That’s far below what the naked eye can see!  Gary Thull Pools says, “Hello DE filter, come help me keep my pool water beautiful and sanitary.”

Check back next week for installment #2 on filters….


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