Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: Chronic low chlorine

  1. Back To Top    #1

    Join Date
    Jun 2013
    Marietta GA

    Chronic low chlorine

    FC 0.23
    TC 1.29
    pH 7.6
    TA 145
    CA 96
    CYA 40

    Please help! My chlorine levels are consistently low after adding the Pool Calculator's recommended amount of bleach. The results I'm getting are consistent with pool store analysis. The water appears clear and clean.

    How does an inline chlorinator figure in to the BBB method? I've also attempted raising chlorine level by increasing dial flow on the chlorinator.

    Thanks from a beginner
    23K gal IG vinyl, 22" Hayward sand filter, mod#S220T (flow rate 20 GPM), 1hp UtiliTech pump (2 speed I think) mod#QIP100. Using LaMotte ColorQ 2056 Pro 7 for water analysis. Pool was installed 07/1997.

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    SW Indiana

    Re: Chronic low chlorine

    When you can't get chlorine to stay in the pool, it's usually a result of low CYA or algae. Your CYA is reasonable, and with chlorine that low, you almost certainly have algae in the pool. If you'll raise the chlorine to shock level for your CYA level (see Chlorine CYA Chart ). Follow the process at Shocking Your Pool

    and keep it there by testing and dosing every few hours for a few days, you'll probably see your chlorine demand drop.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

    Join Date
    Aug 2010
    Dallas, TX

    Re: Chronic low chlorine

    FC of .23 and TC of 1.29 is indicative of algae being in the pool. Time to go through the shock process: pool-school/shocking_your_pool

    Those look like pool store numbers, not numbers from a FAS-DPD test.
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
    If TFP has helped you, please click to SUPPORT TFP!

  4. Back To Top    #4
    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: Chronic low chlorine

    If your numbers are correct, you have CC of 1.06, which means you need to shock the pool.

    There are several possibilities. You might have underestimated the size of the pool. You might have algae consuming some of the chlorine. You might have ammonia in the pool using up chlorine. Your chlorine source might be weaker than you think it is. Your ColorQ might not be working right (less likely, but possible).
    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

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts