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Thread: FCL high - CYA low, hows that??

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    FCL high - CYA low, hows that??

    Previously CYA was high so we emptied and added water. We are getting better, however now the chlorine is high (8.56) and CYA indicates (low)

    I use Color Q Pro7 liquid test kit.
    Chl= high
    Ph = 7.5
    Aly = 89
    CYA = low

    I'm not sure what to do next.... how can I have high chlorine and no cyanuric acid???

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    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: FCL high - CYA low, hows that??

    Welcome to the forum. CYA and chlorine are not joined at the hip. You can have 0 of one and plenty of the other. YOur post seems to imply they are connected as if you add chlorine, CYA is automatically added, too. That's not the case.

    I would suggest you read Pool School "The ABC's of Pool Water Chemistry"

    The other issue probably affecting your testing is the innaccuracy of the Color Q. It has been reported by many here on the foprum that it simply is not reliable when reporting CYA results.
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    Re: FCL high - CYA low, hows that??

    Thanks for your reply. We are campground owners and get inspected by Oswego County Health dept. (NY). They use the Color Q and suggested thats what we use, go figure. Our campers are not very happy when the pool is closed, which does not happen often. When I took a sample to the pool store, they sold me a lot of chemicals and in turn made the pool worse. Just so happened that the inspector came that day and the CYA was 111, they closed the pool. I will try to educate myself more as you suggested although chemistry does not come easy for me.

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    JasonLion's Avatar
    Join Date
    May 2007
    Silver Spring, MD

    Re: FCL high - CYA low, hows that??

    The ColorQ is not very good at the CYA test. However, if you replaced all of the water, I would expect the CYA level to be around zero. Fill water never has any CYA in it. On the other hand, if you only replaced say half of the water, then CYA would be half of what it was before, which couldn't be zero.

    If CYA is really around zero you will lose all of your chlorine to sunlight each sunny day. By watching how much chlorine you lose, you can take a guess at your CYA level. However, the best thing to do is to get a turbidity based CYA tester (such as the Taylor K-1720 or K-1721).
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    Mod Squad zea3's Avatar
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    Jul 2009
    Houston, Texas

    Re: FCL high - CYA low, hows that??

    If you are using stabilized chlorine the CYA would start to creep up, but it would creep up slowly. I would second Jason's advice to get a different CYA test. You can find one here that has enough reagent to run the test 16 times. Be sure to get an accurate CYA reading before you attempt to raise it, you don't want to end up having to drain water again.
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    Join Date
    Nov 2009
    Indialantic, FL

    Re: FCL high - CYA low, hows that??

    Quote Originally Posted by hac
    .... When I took a sample to the pool store, they sold me a lot of chemicals and in turn made the pool worse. ...
    Was any of it a stabilizer product (CYA's "pool store name")?
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    Re: FCL high - CYA low, hows that??

    Also: Read the labels.

    ''(...)-S-triazinetrione'' (basically, if you see ''-s-'' in a chemical name) means CYA.
    ''(...)isocyanuric'' also means CYA.

    Most Pool store clerks (including me if it wasn't for TFP) are not made aware of that and gives ''tricks'' they are taught by the industry that are not derived from actual knowledge, just reflexes taught by the industry.

    Got a pretty shocked face from a colleague when I suggested a customer who had algaes to add a few pucks of chlorine. The learned reflexes is not to use chlorine pucks as long as pool is not okay (unknowingly to avoid High CYA). Customer had alcalinity/pH on the high side and CYA too low to actually be worth anything.

    Sadly the misguided often makes sense when they talk...
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