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Thread: Filter Pressure Increasing After Backflush

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    Filter Pressure Increasing After Backflush

    Hi Everyone,

    I have a one year old, in ground pool and spa with a DE filter, using cellulose fiber. I cleaned my filter within the last two months. I noticed that the water features and spa spillway didn't seem to be flowing as well as they should. On checking, the filter pressure was up near 28-30 psi (the "dirty" range). When I back flushed the filter the pressure dropped to the clean range but returned to high pressure and poor flow after 45 minutes to an hour. I've repeated this a couple of times. I disassembled the filter to look for obstructions. I cleaned the filter and removed some wadded cellulose fiber which I thought would solve the problem. I assume there is an obstruction somewhere in the lines that is moving when I back flush. It may be wadded cellulose fiber somewhere but I'm not sure. I'm guessing the next step is to try to back flush the lines from the skimmers (there are 2) two the filter using a shop vac. Is there a way to do that? I assume that there is some sort of check valve that would be in the way. Any ideas would be greatly appreciated.

    Thanks,

    Doug
    23,000 gal IG Plaster 1989
    Purex Triton FNS Plus DE Filter Model FSNP 60
    1 Hp pump, Polaris 380 w/booster pump
    700 Gal Spa
    Laars Lite Heater T-F 100 Test Kit

  2. Back To Top    #2
    linen's Avatar
    Join Date
    Jul 2010
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    Re: Filter Pressure Increasing After Backflush

    When you have repeated re-cleaned the filter, is it dirty? Sometimes fast filter clogging is a sign of organics in the pool.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Filter Pressure Increasing After Backflush

    It was dirty but not like it was on the previous cleaning. Would organics in the water cause such a large swing in filter pressure in under an hour after back flushing? Thanks for the input.
    23,000 gal IG Plaster 1989
    Purex Triton FNS Plus DE Filter Model FSNP 60
    1 Hp pump, Polaris 380 w/booster pump
    700 Gal Spa
    Laars Lite Heater T-F 100 Test Kit

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    Mod Squad Bama Rambler's Avatar
    Join Date
    Jun 2009
    Location
    SouthWest Alabama
    Posts
    22,347

    Re: Filter Pressure Increasing After Backflush

    If you have a active algae bloom it can clog a DE filter in short order. What does your water look like?
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

  5. Back To Top    #5

    Re: Filter Pressure Increasing After Backflush

    Water is clear and no problems maintaing FC. It looks like the problem is solved. I back flushed it again, this time for about 15 minutes. The pump pressure is down and staying down. I'm not sure what was stopping things up but it looks like it cleared. Thank again for the input.

    Doug
    23,000 gal IG Plaster 1989
    Purex Triton FNS Plus DE Filter Model FSNP 60
    1 Hp pump, Polaris 380 w/booster pump
    700 Gal Spa
    Laars Lite Heater T-F 100 Test Kit

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