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Thread: Cellulose and Sand Filters

  1. Back To Top    #1
    Puffin's Avatar
    Join Date
    Jul 2010
    Metro Atlanta, Georgia

    Cellulose and Sand Filters

    From reading the Adding DE to sand filter article, it sounds like you add DE each time after you backwash. I'm guessing after you do this its normal operation of the sand filter. ie you leave the DE in there until your next normal backwash (when the pressure goes up by 8-9psi) Is this true?

    Also, to complicate things, I used a cellulose alternative. The package says you should backwash after 48hours. Has anyone had any trouble leaving it in until the next time you need to backwash? Like you would with the DE above? Since you use this as a DE replacement, I can't imagine there would be a problem leaving it in longer like you would with DE. I'm guessing is that is suggestion, due to the fact the pressure can build so quickly. I just want to be sure, and see if anyone has any experience with this.

    For some background: I don't have any water issues. Its clear, and water chemistry is good (FC6 CC.5, PH 7.6, CYA 40, TA100, CH 50 Borate~60, Salt ~2000 Temp 58F). Kinda got sparklypoolitis over the summer, I had very few problems (had a mechanical failure I had to deal with), just trying to eek out a but more sparkly out of the pool.

    The Cellulose alternative seems to be working, its been about a day and the pressure has gone up about 3psi, it was a little dark this morning before work so I can't comment on any water clarity improvements. One thing that surprised me was how much alternative it took. The article says 1-2 cups of DE. The packaging had a volume per ft2 listed which came to about 12-13cups for my filter, I ended up using about 13cups to get a 1 psi rise.
    19,600 gal, Vinyl, Grecian L, StaRite Dura-Glas 1 HP pump, 3/4hp booster, Pentair Clean and Clear 420 Cartridge filter
    The Pool Cleaner 4x, PoolSkim

  2. Back To Top    #2
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Cellulose and Sand Filters

    You only need to backwash when the pressure goes up, the same with plain sand, sand+DE, sand+cellulose, etc. As you suspect, the pressure can go up quickly with DE or cellulose added, especially the first time you add it. When first used it will catch a lot of stuff that the sand alone was not able to catch.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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