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Thread: DE Filter Question

  1. Back To Top    #1

    Join Date
    Oct 2015
    San Diego, Ca.

    DE Filter Question

    Am I correct in assuming that when the DE Filter pressure climbs to 25, you can lower that pressure by back washing only and not have to take apart the filter and hose off the grids?
    If so, do you need to re-charge the DE after the back washing each time?
    30,000 Gal. - 40x20x8 - Plaster - SWG Pentair IC 60 - Hayward Pheonix 4x Vacuum - Hayward c1750 Cartridge Filter - Hayward 3/4hp pump - Pool is 45 years old.

  2. Back To Top    #2

    Join Date
    Jun 2016
    Dallas, Tx

    Re: DE Filter Question

    I find that just backwashing get about 75% if the DE out, but leaves big spots with lots of DE. What I usually do is backwash, the take the cover off the filter, remove the drain plug and
    hose out the filter to get the rest. Once a year I will pull the filter out to make sure I get everything.

    Yes you need to recharge after any backwash.
    20K gal Pebblesheen, DE filter, polaris sweeper, Chlorine pool, variable speed pump. City water (alkaline). Direct sun except for very late in the day. Have inline tablet chlorinator
    for when away. Leslie deluxe DPD test kit (I usually just test for CH and PH, get the rest tested at the pool store)

  3. Back To Top    #3

    TFP Guide
    Jimrahbe's Avatar
    Join Date
    Jul 2014
    Bedford, TX

    Re: DE Filter Question

    The forum guideline is that you backwash when the "clean" pressure has increased by about 25%. After every backwash you will need to add about 80% of the amount of DE that you would add when you take the filter apart. The problem is that backwashing only removes some of the dirty DE, each successive backwash removes less and less DE, until you are forced to take the filter apart.

    In my case, I have a vs pump, running at a pretty low RPM, so my normal filter pressure is only a couple of pounds. I never backwash anymore. I have two rent house with DE filters and just clean them twice a year.

    Jim R.
    Finished in 2015 - 17K Gal, IG, 20' x 25' Almost Rectangular Pool, Pebble finish, three rockport water falls. Pentair Equipment: EasyTouch 4, IC40 SWG, 3 HP VS Pump, CCP5200 Cartridge Filter.
    TF100 with SpeedStir and SampleSizer, ColorQ Pro 7, Dolphin Premier Robot Cleaner, added Screen Logic 2.

  4. Back To Top    #4

    Join Date
    May 2016
    Swansea MA

    Re: DE Filter Question

    I am a bit of newbie here but, would say it depends on the exact filter you have. I have a DE filter that looks just like a sand filter from the outside with a multi position handle on the top. Mine has like a million (sarcasm) bolts to take the top off. I was told to just backwash and recharge. My neighbor on the other had has no position handle on the top and like a big snap ring belt thing to take the top off his. I think that style requites to rinse out the grids every time. Either way you always need to recharge the DE.

    Hope that helps.
    24 ft round AG 12,700 gal. vinyl
    Doughboy Sequel II Rotary DE filter
    TF-100 test kit. 1st full season

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