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Thread: Chemical Balance on covered pool

  1. Back To Top    #1

    Join Date
    Jun 2010
    Austin, TX

    Chemical Balance on covered pool

    So I am a relatively new owner of a small covered pool. I have read the pool school multiple times and keep a printed copy near my TFT-100 test kit. I have not had much trouble at all adjusting chemicals thanks to this site and the pool calculator.

    My question is if I should adjust my chemical targets based on having my pool covered 100% of the time unless I am actually in the pool. (The only exception is leaving it uncovered at night in the summer to lower the temperature of the water).

    Here are my current numbers:
    FC: 3.5
    CC: 0
    TC: 3.5
    TA: 100-110
    CYA: 40-50
    pH: 7.5
    CH: 210-220 (just added another 8oz to raise it more last night, my target is 250)
    Salt: 3100
    Temp: 86

    My main question is about CYA. Because my pool is so small and it is covered all the time my FC can rise very easily and it takes a while to drop back down. I have found that 15% is too high a setting on my turbo cell 15. I run it between 8-10% normally (9 hour pump run time a day).

    Do I still need to raise my CYA up to 70-80 when the water gets only limited sun?

    Also, I have been repeatedly lowering my pH to 7.0-7.2 with muriatic acid and letting it drift up with very little success in lowering my TA. Am I doing something wrong in my attempts to lower TA?

    What about my other numbers? Should I run a lower FC since my pool is covered most of the time?

    Thanks for any advice.
    3900 Gallon (18 x 8.5 x 5) Partially In Ground Fiberglass Pool -- 2" Schedule 40 PVC -- Hayward P4 Controller -- Goldline Aqua Rite Turbo Cell Salt Chlorinator -- Hayward 2 Speed Max Flo II 1 HP Pump -- Hayward SwimClear 225 sqft Cartridge Filter -- Hayward 250K BTU Natural Gas Heater -- Endless Pool Fastlane Swim Machine -- Cover Pools Manual Track & Reel Security Cover -- TF-100 Testkit

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

    Re: Chemical Balance on covered pool

    Using a SWG with a pool that is covered all of the time is problematic. Chlorine usage will vary dramatically depending on how much you use the pool, instead of being more or less constant because of sunlight. That can lead to wild variations in the FC level if you aren't paying enough attention and adjusting the percentage setting based on how much you use the pool.

    Yes, it is reasonable to lower the CYA level to 30 to 50 if you are going to keep the pool covered nearly all the time, and reduce the FC target level correspondingly. With CYA at 50 and a SWG, FC should be between 2 and 4.

    Keep in mind that covered pools are prone to having CC problems. If CC gets to be an issue you will want to open the cover occasionally while it is sunny to help burn off the CC.
    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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