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Thread: Backwashing and chemicals

  1. Back To Top    #1
    botanica37's Avatar
    Join Date
    Feb 2009
    Oakton, VA

    Backwashing and chemicals

    My first opening by myself was yesterday, it took all day and several online searches for manuals and stuff...but the pool is open: a nasty, smelly brown swamp (pondering if I closed it incorrectly?). I am running the filter and took the first set of tests:

    FC 0
    PH 8.2
    TA 60
    CH 160
    CYA 60
    temp 54

    So here is what I am thinking:
    1. lower the ph first to 7.5

    and then not clear what to do first: do I shock the pool and add calcium to get the CH up and the TA or fix the CH first and then shock it? Is there a particular order in adding the chemicals?

    and 2. Obviously I need to backwash a lot...but how does the filter backwash with the super nasty brown soup? What I mean is that I am not going to see clear water coming out of the backwash for a while, right?

    and 3. On the pool calculator am I correct in assuming that I need to balance the values in the right field so that the CSI shows balanced?

    Thanks for the help!
    free form 40k gal, IG, plaster, Triton II 100C sand filter, Lite 2 heater
    1 1/2 HP Pentair Ultra Flow High Performance pump
    Caretaker in-floor cleaning system

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

    Re: Backwashing and chemicals

    Welcome to TFP!

    Once the pump is running, the first thing to do is lower the PH. Second is to shock the pool and get everything cleaned up. None of your other levels require immediate attention, and can wait till shocking is complete.

    Dirty pool water can make figuring out when backwashing is complete more difficult. There should still be an obvious transition from extremely dirty to only kind of dirty, but you will probably need to keep a closer eye on it to spot the difference.

    You don't generally need to worry about getting CSI balanced exactly unless you have some special situation you haven't mentioned. As long as you can stay within the recommended levels for a plaster pool from the article at Pool School, you don't need to worry about CSI.
    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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