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Thread: DE in sand filter

  1. Back To Top    #1

    Join Date
    Jul 2014
    Hudson, wi

    DE in sand filter

    I have been having some fine brown dust material show up for as long as I have had the pool (not very long). I vac it up and it keeps coming back, not a big deal, I assume it is dust or pollen or something. I finally got to the point where I wanted to try adding DE to my sand filter to cut down on the "dust". After I added enough DE to raise my pressure by 1psi I now have white dust (I am assuming DE material) on the floor of my pool. Is this normal and will it continue to do this? Just wondering if the filter should be getting all this. Will a robot be able to keep this "dust" out of the pool? I was planning on getting one for next season. Thanks
    21,000 gallon IG with vinyl liner, Pentair sand filter, TF100 test kit, pool is about 15 years old.
    new in 2016 - Hayward SWCG with T15 cell

  2. Back To Top    #2
    twesterd's Avatar
    Join Date
    Aug 2014

    Re: DE in sand filter

    It sounds like the DE passed through the sand filter and went back to the pool. I have a filter designed for DE and if the filter panels have any holes, what you describe is what happens: instead of the particles staying caught in the filter, they pass through the hole and get dumped back into the pool.

    NOTE: I didn't know I needed to turnoff the valve to my robot the first time I added DE to my filter, and it jammed the filter for the robot and sent DE all over the bottom of my pool as the filter for the robot wasn't designed for DE. I originally thought my filter panels were bad.

    FYI: I have no idea if DE can be used with sand filters. The DE filter panels I use have a very fine mesh to trap the DE. With DE covering the surface, it traps even smaller particles. However, it also restricts water flow, that is why there are so many panels with very large surface areas to allow enough flow. Does DE get trapped by the sand and then result in trapping even finer particles? Would it clog the sand filter and restrict flow such that its not really cycling; therefore, not cleaning much water? Will DE just pass straight through? I don't know.

    Besides the pressure gauge, I can tell when my filter requires cleaning by looking at the water in front of the pool light at night. If I see a bunch of particles floating by in the water, its not working so good anymore. If all I really see is air bubbles, and no particles, its working great. Maybe your sane filter needs cleaning, or sand replacement, or some other form of maintenance? I know nothing of sand filters.
    In-Ground Gunite Pool: 10,000-13,000 Gal, Filter: DE Triton Purex FNS Plus 48
    Pump: A.O Smith 1.5 HP Motor attached to 2HP Self-priming pump, Pool Installed: 1994
    Test Kit: Leslie's Complete Pool Care DPD Test Kit and LaMotte ColorQ Pro 9 (love and use both)
    Cleaner: Polaris 360 Pressure Side

  3. Back To Top    #3
    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: DE in sand filter

    No, this is not normal. It sounds as though the sand is channeled. That is to say, it has hardened into clods and the stuff it should be filtering is slipping out through the cracks between them.

    The solution is a deep cleaning. I suggest you backwash to get the layer of DE out, and then open the filter up and break up the clods and clean things out as described in this thread:
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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