What Is a DE Pool Filter and How Does It Work?

Updated on June 5, 2017
robhampton profile image

Being in the pool service industry for so many years, I have taken apart and serviced literally hundreds of DE filters

DE Filter
DE Filter

What is a DE Filter?

A diatomaceous earth filter (aka a DE filter) is composed of several grids that hold the diatomaceous earth powder. They are sometimes known in the business as "water polishers," since they are capable of filtering particles as small as three microns (in comparison, a grain of salt is about 90 microns in size). Anything smaller than 35 microns is invisible to the naked eye. This is why I tend to rave so much about DE filters. They are by far the best filtration available for swimming pools.

A DE filter requires back-washing less often than sand or cartridge filters. With a good working DE filter, your pool water will have far fewer problems than with other filters. In my article about how to clean a green pool, I was able to vacuum the pool without by-passing the filter to an external drain source since the DE filter captured every bit. A cartridge or sand filter would have allowed the algae to shoot back to the pool through the returns.

Torn Filter Grid
Torn Filter Grid

DE Filter Maintenance

Are they easy to maintain? Absolutely.

  • On average, it will only need to be back-washed once a month.
  • Grid inspection is recommended after a year. Check for rips or tears on the grid material and rinse thoroughly, as the DE can build up over long periods of time.
  • If a grid is torn, it can simply be replaced. It can be re-covered, but buying a new one costs about the same and is much easier.

Make sure you have a functioning pressure gauge.
Make sure you have a functioning pressure gauge.

How to Back-Wash the DE Filter

This is a pretty simple procedure. After you have done this a few times, you'll get to know what the normal clean filter pressure is for your system. This depends on pump horsepower, returns, etc. They all vary.

In this case, let's say normal clean filter pressure runs around 22 PSI. If the gauge is reading 25 or 26 PSI, that just means the filter is doing its job and starting to get dirty. In this scenario, it would need to be 30 to 32 PSI to indicate that it needs to be back-washed.

Shut off the pump and position valve to "backwash."
Shut off the pump and position valve to "backwash."
Filter being backwashed.
Filter being backwashed.
  1. Before you reposition the "multi-port" valve, be sure the pump is off.
  2. Select the "backwash" position then turn the pump on.
  3. Backwash for three minutes. This will get a lot of the old DE powder out.
  4. I usually return the valve to the "filter" position and run for another minute, and then backwash again for another minute. This ensures the filter grids are clean.
  5. With the valve positioned back to the "filter" position and the pump running, you will add around four pounds of DE powder through the skimmer. (Consult your DE filter's owners manual to discover your filter's square footage and exactly how much powder to add.)

That's it! you're done. Keep an eye on the pressure gauge and you shouldn't need to back-wash for about a month.

Return to "filter" position.
Return to "filter" position.

How to Tell If Grids Need Replacing

There is a very easy way to tell. When you add the DE powder, wait for a minute. If you have torn grids or a broken manifold, the DE powder will come right back into the pool through the returns. Time to take the filter apart!

Add DE powder through skimmer.
Add DE powder through skimmer.

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.


Submit a Comment

No comments yet.


This website uses cookies

As a user in the EEA, your approval is needed on a few things. To provide a better website experience, dengarden.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://maven.io/company/pages/privacy

Show Details
HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
LoginThis is necessary to sign in to the HubPages Service.
Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
AkismetThis is used to detect comment spam. (Privacy Policy)
HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
MavenThis supports the Maven widget and search functionality. (Privacy Policy)
Google AdSenseThis is an ad network. (Privacy Policy)
Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
Index ExchangeThis is an ad network. (Privacy Policy)
SovrnThis is an ad network. (Privacy Policy)
Facebook AdsThis is an ad network. (Privacy Policy)
Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
AppNexusThis is an ad network. (Privacy Policy)
OpenxThis is an ad network. (Privacy Policy)
Rubicon ProjectThis is an ad network. (Privacy Policy)
TripleLiftThis is an ad network. (Privacy Policy)
Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
ClickscoThis is a data management platform studying reader behavior (Privacy Policy)