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Thread: Acceptable chlorine loss over 24 hours

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    Acceptable chlorine loss over 24 hours

    Hi
    My pool is covered and I have a thermal blanket so no UV degredation and no bather load
    Because I'm getting low on reagents (already ordered) I am only testing once in 24hrs
    I have a chlorine loss of 1.5ppm in 24hrs. Would that be acceptable to pass the OCLT
    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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    Mod Squad Texas Splash's Avatar
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    Re: Acceptable chlorine loss over 24 hours

    Hello! Well, remember that an OCLT (Overnight Chlorine Loss Test) and the amount of FC lost in 24 hours are two different things. If you only lost 1.5 FC in 24 hours (example 5:00pm 23 Mar to 5:00 PM 24 Mar), that's great. But if you lost 1.5 FC from dusk to dawn (say 9:00PM to 5:00 AM) that's not good. Make sense?
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Swampwoman's Avatar
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    Re: Acceptable chlorine loss over 24 hours

    Hi Dennis. IMHO, the OCLT is only valid when tests are taken from dark til dawn, 8ish hours, meaning 2 tests. Anything else is a guess.

    With that said, I would not be alarmed over a covered pool losing 1.5 ppm n 24 hours UNLESS I had other indications of nascent algae, eg. Slight cloudiness to water.

    So I guess my question is why are you wanting (but unable to) perform the OCLT. Have you been slamming?
    In ground vinyl Grecian, 24k gal, Hayward 220t sand filter, VGreen VSP 165, Hayward SWG, Raypak NG 265k heater, dolphin m4.
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    Re: Acceptable chlorine loss over 24 hours

    Hi Texas Splash and Swampwoman

    The loss was over 24hrs
    The water is clear but I have been having trouble maintaining chlorine after AA treatment and only now does it appear to stabilise
    I was concerned that I may have had some invisible algae and I slammed the pool
    I'm very low on reagent and it's not due untill the 3rd of april so I want to be frugal with the testing
    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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    Swampwoman's Avatar
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    Re: Acceptable chlorine loss over 24 hours

    Hi Dennis. I realize its too late for the advice but so you know next time, don't slam after an AA treatment (unless youre POSITIVE you need to) as it wears down the metal sequestrant and risks returning of the staining.

    Leftover AA always fights chlorine until its broken down by same, so the trick is just to keep topping it up until stable. Between now and when you get your reagents, just be sure to maintain you FC to TFP regs and you should be fine There is no need for an OCLT at this time.
    In ground vinyl Grecian, 24k gal, Hayward 220t sand filter, VGreen VSP 165, Hayward SWG, Raypak NG 265k heater, dolphin m4.
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    Re: Acceptable chlorine loss over 24 hours

    When I finished the AA I kept the chlorine to the minimum as per the instructions for 2 weeks added sequestrant but it still wasn't holding
    That's when I started the slam
    The FC is at 7 now, ill drop it to 5 and add more sequestrant


    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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    Swampwoman's Avatar
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    Re: Acceptable chlorine loss over 24 hours

    No need to drop it at 7 ...just SLAM levels are the issue. Mine works fine in water that's 6 ppm-80 cya (saltwater.)
    In ground vinyl Grecian, 24k gal, Hayward 220t sand filter, VGreen VSP 165, Hayward SWG, Raypak NG 265k heater, dolphin m4.
    If TFP has helped you, please click to SUPPORT TFP!
    Helpful Links:
    GET A TEST KIT Chlorine/CYA Chart How to SLAM About Metals & Stains

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    Re: Acceptable chlorine loss over 24 hours

    My SLAM level is 10 because my CYA IS 20 (covered pool)


    10,000 gallons inground Leisure fibreglass pool, Hayward powerline pump, Quality120 glass media filter, 27kw output air source heat pump and thermal cover.
    Retractable cover with Polycarbonate roof and glass side for all year round use. K-2006C test kit and Speed stir

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