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Thread: Bleach shelf life?

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    Bleach shelf life?

    How long will my bottles of 8.25% bleach last? I normally just pick up a few bottles when I go do our family grocery shopping every 2 weeks throughout the year so that by the time pool season starts, I have my bleach for the season.

    the bottles are stored upright on shelves in my wooden shed year round.
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    Smykowski's Avatar
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    Re: Bleach shelf life?

    Light and heat are the enemy. The darker and colder your storage place, the longer it will last. Search for "bleach shelf life," chem geek posted a great article a few years back that can answer your question better with numbers.
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    Re: Bleach shelf life?

    found it:

    http://www.troublefreepool.com/threa...life-of-bleach

    it does a good job explaining it, BUT, one question I still have that it didnt answer:

    exposure to summer heat obviously causes strength degradation, but what about extreme cold?

    if I buy 8% in december when its cold, will it still be 8% come about now..?
    Partially buried Doughboy Desert Spring 16 x 32, sport pool, with 7 ft deep middle, 20,000 gallons, Hayward Powerflo Matrix 1.5 HP 2 speed pump, 250 lb sandfilter, 2 Doughboy skimmers and 2 returns. 2 cascade fountains.
    Taylor K-2006 kit. Zodiac Barracuda Ranger suction side cleaner.
    TFPC method and is crystal clear every day thanks to TFP!!!

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    Re: Bleach shelf life?

    As shown by the table at the bottom of this link, the rate of degradation is a function of both temperature and concentration. For 8.25% bleach, figure losing about half its strength in 6-7 months at 90F but a year at 80F so keeping the chlorine cooler helps a lot. This assumes the chlorine is of high quality with no metal impurities that speed up its degradation.

    As for cold, that is not a problem and I'm assuming you aren't talking about freezing.
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    Re: Bleach shelf life?

    Quote Originally Posted by chem geek View Post
    As shown by the table at the bottom of this link, the rate of degradation is a function of both temperature and concentration. For 8.25% bleach, figure losing about half its strength in 6-7 months at 90F but a year at 80F so keeping the chlorine cooler helps a lot. This assumes the chlorine is of high quality with no metal impurities that speed up its degradation.

    As for cold, that is not a problem and I'm assuming you aren't talking about freezing.
    awesome. Thanks chemgeek! And no, even when it gets freezing temps outside, I have not yet had the bleach itself freeze in the shed.
    Partially buried Doughboy Desert Spring 16 x 32, sport pool, with 7 ft deep middle, 20,000 gallons, Hayward Powerflo Matrix 1.5 HP 2 speed pump, 250 lb sandfilter, 2 Doughboy skimmers and 2 returns. 2 cascade fountains.
    Taylor K-2006 kit. Zodiac Barracuda Ranger suction side cleaner.
    TFPC method and is crystal clear every day thanks to TFP!!!

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    Re: Bleach shelf life?

    The freezing point of 8.25% bleach is around 15F, so you have plenty of margin once air temps dip below 32F before you need to be concerned about the bleach freezing.
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