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Thread: Chlorine Lock?????

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    Chlorine Lock?????

    I have had a pool for 15 years and I am having a problem with free chlorine. I have a 23k gallon vinyl pool. Had the water tested at a pool store. My pool will not hold free chlorine. I am told I have chlorine lock and shocking should take care of it. I have shocked it 2 days in a row. The first day with 4 gallons of liquid shock. The second day with 5 gallons of liquid shock. No luck. There is still no free chlorine. I have read that removing the phosphates might do it. Any suggestions?

    Total chlorine 1.9
    Free chlorine 0.3
    pH 7.3
    Total alkalinity 110
    Calcium Hardness 75
    Stabilizer 25

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    Mod Squad JohnT's Avatar
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    Re: Chlorine Lock?????

    Welcome to TFP. You might want to read Shocking Your Pool for guidance. Chlorine can be consumed rapidly, and your 5 gallons of shock could have been used up within a few hours by algae or other contaminants and sunlight.

    25ppm for stabilizer sounds suspicious to me. It is difficult to test at thaat low level, and most pool users tend to have much higher levels unless they practice the philosophy we endorse. Pool store test results are notoriously unreliable, so you may want to try another store to get some confidence in then numbers before you take any action, but if it is really 25ppm, that is part of the problem. Sunlight rapidly consumes chlorine unless it is protected by CYA (stabilizer).
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    bmann71's Avatar
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    Re: Chlorine Lock?????

    Welcome

    Follow JohnT's advice and here's a thread started by one the experts on this site discussing this in case you want to read about it.

    http://www.troublefreepool.com/debun...th-t30013.html

    cheers
    Ponduke
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    Butterfly's Avatar
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    Re: Chlorine Lock?????

    "Chlorine lock" is misleading/confusing pool store jargon. In practice it seems to be what people say when they can't explain what is happening.

    Forget about the phosphates. Phosphate remover primarily exists to make money by selling it.
    And, phosphates don't matter in a well balanced pool.


    The best thing you can do for you pool is order one of the recommended test kits - comps in Pool School.
    The fav around here is the TF100, link in my sig . Best bang for the buck, fast shipping, excellent service + the owner, duraleigh, also owns this site and is here helping folks with their pools all the time.

    Pool School button is located upper right of each page. With a reliable testkit & Pool School, you will be in charge of your pool well on your way to a Trouble Free Pool summer.

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    Re: Chlorine Lock?????

    Thanks all. I just came back from a different pool store and they told me to add dichlor granular pool shock to the pool. If it did not dissolve clearly and there was any reaction such as cloudy water then there is something attacking it and it is probably bacteria. The pool is crystal clear but sure enough when I added the shock it turned milky. They want me to add 15-20 lbs of granular shock to get rid of the bacteria. Any thoughts?

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    Re: Chlorine Lock?????

    RUN from that pool store and get your own test kit and everyone on this forum can help you figure out what is really going on.
    14,750 GAL IG Fiberglass (16 x 33) NE Ohio || Jandy 1HP 2 speed Pump || Waterco MultiCyclone 16 Centrifugal pre-filter (removed due to not working with sand filter) || 30" 575 Lb. Sand Filter || AquaCal 140K BTU Heat Pump || Solar Cover || Inter-fab Adrenaline Slide || GLI Monsoon Solar Cover Reel || K-2006C Test Kit || BBB with Liquid Chlorine Stenner Injection || Rayner Mighty Mesh Winter Cover

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    Isaac-1's Avatar
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    Re: Chlorine Lock?????

    20 pounds of dichlor in a pool your size would send the CYA level through the roof.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    Re: Chlorine Lock?????

    Quote Originally Posted by PoolHelpPlease
    Thanks all. I just came back from a different pool store and they told me to add dichlor granular pool shock to the pool. If it did not dissolve clearly and there was any reaction such as cloudy water then there is something attacking it and it is probably bacteria. The pool is crystal clear but sure enough when I added the shock it turned milky. They want me to add 15-20 lbs of granular shock to get rid of the bacteria. Any thoughts?
    PHP, not meaning to sound harsh, but you really need to decide if you want to follow our recommendations or the pool store. They do not mix well.

    Our methods are tried and true and once you gain the knowledge, your pool will NOT become overstabilizied again without your already knowing the reason why.
    TFP Moderator TF100 Test Kit TF100 TestKit YouTube Channel PoolMath
    You're done SLAMing when:
    1)You lose 1ppm or less FC overnight, & 2)You have .5ppm CC's or less, & 3)your water is clear.

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    JasonLion's Avatar
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    Re: Chlorine Lock?????

    Quote Originally Posted by PoolHelpPlease
    The pool is crystal clear but sure enough when I added the shock it turned milky.
    That sounds just like calcium clouding, something that results from using cal-hypo when some combination of PH, TA, and CH levels are on the high side. Calcium clouding has nothing at all to do with bacteria and usually goes away by it's self, or if it persists you should lower the PH to 7.2 and that will almost always take care of it.

    A pool store employee who doesn't know that is incompetent, and if they did know it they were trying to con you. By the by incompetence is rather more common than you might expect.
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    mickey4paws's Avatar
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    Re: Chlorine Lock?????

    Hi, and welcome

    I went through a similar thing with our pool not holding chlorine. I followed the shock process here in Pool School. It took about 4 days, but things are great now. Make sure to follow the shock process and also the overnight chlorine loss test.

    As others have said, run from that pool store. 20 pounds of dichlor is insane!
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