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Thread: Adding DE to Sand Filter question.

  1. Back To Top    #1

    Join Date
    Aug 2016
    Byron, Il

    Adding DE to Sand Filter question.

    So I got some DE to add to my sand filter as it was taking a long time to clear the water. Oddly enough I pulled the cover off and despite the bottom have a nice layer of gunk the water was very clear. I decided to add the DE anyway.

    Followed the instructions I noted the pressure, barely below 15 PSI, and started adding DE by 1/4 cups. The instructions say 1 to 2 cups usually raises it the required 1 PSI. I stopped at 2 cups and the needle had barely moved, I'd say not much more then 1/3 PSI.

    I decided to go ahead and vacuum the gunk and I guess the DE was doing it's job because as I vacuumed the pressure went up. It went up considerably enough that I decided to Backwash. After back washing the pressure dropped down even further the the original 15 PSI.

    So two questions.

    1. Do I continue to add more DE even over two cups until the pressure goes up one PSI?
    2. By back washing did I remove all the DE. I ask this one because I vacuumed ~ 2/3rds of the pool and the pressure went up pretty quickly. I then back washed and finished vacuuming and the pressure didn't seem to move for the final third. This is pretty much how it worked before adding the DE.


    15K gal, IG vinyl, Sand Hayward, Hayward Pump single speed, Install 2004, TF-100, city water.

  2. Back To Top    #2
    banditig's Avatar
    Join Date
    Sep 2015

    Re: Adding DE to Sand Filter question.

    When you backwash, most of the DE will go to waste, but not all of it. It's mostly trial depending on flow rate, size of filter and pump. About 1 cup is most I add dilute first.
    15x54 swim & play vinyl metal wall AG
    Hayward S210T sand filter 1.5 HP Pentair Superflo vs
    Rheem raypak 130,000 BTU mv ng
    TF-100 test kit, HM digital com100 Wanda the Whale

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