Add some DE to a sandfilter

May 14, 2008
South Central PA
I heard that you could add some DE to a sand filter to improve filtrations
From what I understand you take a 1/3 of a cup of DE mix with water and add to your skimmer.
You do this process untill you get a 1psi increase at the filter. Than when you backwash you
add new DE.

Please comment if this really works or is a bad idea



Well-known member
Jun 26, 2007
I do it, I add about 1/4 to 1/3 cup to my filter and it does wonderfully. I actually raises it about 3 psi, but that's not alot. When I backwash I add 1/4 to 1/3 again, until the psi goes back up. It filters better, it filters out algae etc faster, and is just all around better.


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TFP Expert
May 7, 2007
Silver Spring, MD
Yes, adding DE to a sand filter works well. I suggest adding 1/4 cup of DE mixed into a pail of water to the skimmer, give it five minutes to settle down and then check the pressure increase. Repeat this process till the pressure has gone up 1 psi. After the first time you can simply put the correct amount in all at once (premixed into a bucket of water). If you have a skimmer sock be sure to remove the skimmer sock, or entire basket, while adding the DE.

If you are getting a 3 psi increase in pressure, try using less DE next time.