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Thread: Low CYA and high TA

  1. Back To Top    #1

    Join Date
    Sep 2007
    Liberal, Missouri

    Low CYA and high TA

    Our pool was completed on May 22 and some quantity of copper algaecide and metal sequester were added at that time. On May 27, the PB put start-up chemicals in the pool - 3 bags of shock, 4 lbs of CYA (via the skimmer), and put pucks in the inline chlorinator. On May 30, we backwashed (lots of dirt from pool construction) due to an increase in filter pressure.

    I have tested the water daily since May 29 using the TF Test Kit. These are my numbers as of June 1.
    FC 2.5
    CC 0
    TC 2.5
    PH 7.8
    TA 160
    CYA The tube filled all the way up and I could still see the dot. So I assume it is less than 20.

    I have a couple of questions.
    1. Do I need to add more CYA or wait for a few more days?
    2. Do I need to adjust the TA or not?
    25K gal, Vinyl, 18x36 Rectangle IG, 1.5 HP pump, sand filter with Zeobrite

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana
    Sounds like a smart PB. He put in about half what you need. will help you figure out what you need. I'd probably add about 2 more pounds, which according to my figuring is about half what you need. Going by halves ensures you don't overshoot, or if you do, not by much. Wait a week between additions to allow the CYA to dissolve and mix in with the water.

    I wouldn't get very concerned about the TA. Lower your pH, and the TA will come down. Lowering the pH enough, and you can aerate the water to lower your TA. There's a Sticky Article on how to do this.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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