One of the secrets to keeping your pool water blue, clear and safe for your family is to ensure that your filtration system is running properly.  If you own a “D.E.” filter, you should make sure to clean out your filter at least once year, and in some cases you will need to do it more often. This post will discuss why.

The three typical types of filters are 1) sand filters, 2) cartridge filters, and 3) Diatomaceous Earth filters. Since Diatomaceous Earth, while fun to say, is difficult to spell, so we usually abbreviate to “D.E.”  This post is specifically geared to the owners of DE filters, because they typically require the most maintenance.

DE filters work by capturing dirt and other contaminate particles on the Diatamaceous Earth and the grids. In theory, the process of backwashing pool water in a reverse direction discharges the DE and the captured contaminates onto your lawn. Then, in theory, you refresh the grids with clean DE through the skimmer suction lines. That is the theory. Reality isn’t so nice and neat.

What happens in practice is the DE gets sticky from body oil, suntan oil, human sweat, tree pollen, dog and human hair and other matter we don’t want to talk about. When DE gets sticky like that it sticks to the grids and no amount of backwashing will get it off. It starts to form clogs that I like to call DE “bricks” on and in between the grids.  You will know when you are getting sticky clogs because the pressure on your filter goes up, and no amount of backwashing gets it to normal, clean running pressure.

Some “professionals” and even some manufacturers suggest that you don’t have to worry unless your pressure is 10 psi above normal. Hogwash. I dare you to open up your filter that is trying to run at 10 psi above normal. Double dare you. Don’t eat lunch first, because I guarantee you will be grossed out, and that filter is so packed, you probably have cracked the grids and or the manifold, which will cost you hundreds of dollars in parts, even if you do the repair yourself. Not to mention you have really are not doing your family any favors to their health by kidding yourself that the filter is really cleaning that water. You are just running water through increasingly thick layers of contaminated filthy DE.

South Austin Pool Service recommends that you (or your service provider whether it us or someone else) open up your filter and hand wash the grids AT LEAST once a year, and more often it is needed. Our personal guideline based on many years of experience is whenever you can’t get the filter back down to within 3 PSI of the clean running “normal.” A great time of year to clean your filter is late April or early May: after the live oak pollen has stopped dropping and before school gets out.  If you have a lot of hot, sweaty, suntan oiled people swimming in your pool during high season, you may need to clean it out more often than once a year. If your filter is too small for your filteration needs, you may need to clean it out more frequently.