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Thread: Chlorine degrading

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    tcat's Avatar
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    Chlorine degrading

    How fast does chlorine degrade in 100 degree temps? I ask because I typically fill my 15g tank with 10g of 8.25%. I added 4g of "Awesome Bleach" from Dollar Store a while ago, and pretty sure things got diltued to about 5 or 6%. But at 100 degrees with tank in sun, I'm wondering if the tank has like 3% in it now.... I keep having to run my timer longer and longer to keep FC above 3. Just curious if I should stick with less than 5g in the tank at anytime. I normally use 32oz/day, up to 48oz now and probbaly need to add more.
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
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    Re: Chlorine degrading

    This page gives a general idea of what your looking for: http://www.odysseymanufacturing.com/about_product.htm. I would say the suns uv rays are worse than the heat. Can you shade the tank?
    16k AG Vinyl Sand Filter

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    Re: Chlorine degrading

    See this post that shows that in 100F temperature 8.25% bleach drops to 5.8% over one month. Keep in mind that this would be for constant 100F but you probably have lower nighttime temps. Based on this link in August the daytime average is 97F while the nighttime is 75F. So with that 22F temperature difference the effective average temperature is 75+15 = 90F. So the degradation would be from 8.25% to 6.75% over one month.

    Note that the worst thing possible is for the tank to be exposed to the UV of sunlight so I hope that the tank is fully opaque to UV (preferably opaque to all sunlight and either in the shade or a white or reflective tank so that it does not absorb heat).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    tcat's Avatar
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    Re: Chlorine degrading

    Thanks! It's been hot with no rain for a couple months. I could see 8.25 going to 6 with cheap bleach (never again!), and probably to 4 with the heat. Tank is white but full sun at least 5 hrs a day. May buy a metallic water heater insulating jacket for it. May need to find a place in the house to store the stock, since it's probably 90 degrees in the garage most of the summer.

    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

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    EVChargeGuy's Avatar
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    Re: Chlorine degrading

    As a follow up to this thought, will 12.5% Liquid chlorine degrade to zilch over a northeast winter?

    It looks like may have gotten over zealous with my last purchase of LC and may still have a 2-3 cases after the pool gets closed.
    IG Tear Drop, Dark Gray Gunite , 27,000 gallons -Age 50+-years, very old Hayward Split Egg Sand Filter with side mount Multi-port- Hayward SP2600VSP Pump- Hayward chlorine feed (not used since finding TFP) - Laars 315K BTU Oil heater- LoopLoc Safety cover- AquaBot RAPIDS 4WD- TF-100 Test Kit w/ Speedstir- 390 Gal Hot Springs Spa Envoy installed May 2017

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    Re: Chlorine degrading

    It probably won't degrade completely to zero. If you read the post chem geek linked to it shows that even after 6 months in 70-100 degree weather it only degraded to roughly 3.5%. Seems like it mostly stabilizes there.

    So if you store in a cool place out of the sun you should be able to do a bit better than that. Not so much money down the drain, but less value for the dollar.

    From my HTC One via Tapatalk
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Re: Chlorine degrading

    The degradation rate is proportional roughly to the square of the concentration so it slows down considerably as it gets weaker.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    EVChargeGuy's Avatar
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    Re: Chlorine degrading

    Quote Originally Posted by Donldson View Post
    It probably won't degrade completely to zero. If you read the post chem geek linked to it shows that even after 6 months in 70-100 degree weather it only degraded to roughly 3.5%. Seems like it mostly stabilizes there.

    So if you store in a cool place out of the sun you should be able to do a bit better than that. Not so much money down the drain, but less value for the dollar.

    From my HTC One via Tapatalk
    thx, If this winter is like last year, it will most likely be 6 months of below 40 degrees.
    IG Tear Drop, Dark Gray Gunite , 27,000 gallons -Age 50+-years, very old Hayward Split Egg Sand Filter with side mount Multi-port- Hayward SP2600VSP Pump- Hayward chlorine feed (not used since finding TFP) - Laars 315K BTU Oil heater- LoopLoc Safety cover- AquaBot RAPIDS 4WD- TF-100 Test Kit w/ Speedstir- 390 Gal Hot Springs Spa Envoy installed May 2017

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