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Thread: CYA Testing

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    CYA Testing

    Does anyone know if it is possible to get a false low CYA reading? I just shocked my pool with more dichlor than I thought I needed and my pool is still light green. I did a chlorine test and it reads zero and I did a CYA test and it shows virtually none. My pH is about 7.2. Any ideas?
    Steve
    Atlanta, GA

    Inground Vinyl, 30,000 gallon, 20x40 Lagoon, Pentair Single Speed 1-1/2 hp Superflow, Pentair SD 80 Sand Filter, Polaris 280 cleaner w/ Booster pump, Pentair Easytouch.

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    Butterfly's Avatar
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    Re: CYA Testing

    How much dichlor did you add?

    What was your CYA level before, or the last time you tested and when?

    What is the water temperature? Did you warm the sample to room temp before testing?

    Pool still green and FC zero? Sounds like algae ate up FC.

    How much time between addition of dichor addition and CYA testing?...and was pump running the entire time?

    Do you have a complete set of test results before you started shocking?

    We'll help, but need more info ..........so many variables.....
    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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  3. Back To Top    #3

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    Re: CYA Testing

    I added 4 lbs of dichlor. I did not do a CYA test before so I don't know what it was before. I did not get the water to room temp. before testing. It has only been a couple of days since I added the dichlor but the pump has been running pretty much the whole time. I do not have a complete set of test results prior to shocking...

    Sounds like I've made a lot of mistakes...but thanks for the help!
    Steve
    Atlanta, GA

    Inground Vinyl, 30,000 gallon, 20x40 Lagoon, Pentair Single Speed 1-1/2 hp Superflow, Pentair SD 80 Sand Filter, Polaris 280 cleaner w/ Booster pump, Pentair Easytouch.

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    Richard320's Avatar
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    Re: CYA Testing

    Situations like this are where the free testing at the Pool Store comes in handy.

    Just sayin'
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: CYA Testing

    CYA below 20 ppm can easily read as zero. You can use the pool calculator to calculate how much the cyanuric acid would rise for a given amount of dichlor. For your 30,000 gallon pool, 4 pounds of dichlor would raise your FC by 8.9 ppm and your cyanuric acid by 8.1 ppm.

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    Re: CYA Testing

    James,
    How do you figure out how much CYA is added by the dichlor?
    Steve
    Atlanta, GA

    Inground Vinyl, 30,000 gallon, 20x40 Lagoon, Pentair Single Speed 1-1/2 hp Superflow, Pentair SD 80 Sand Filter, Polaris 280 cleaner w/ Booster pump, Pentair Easytouch.

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    Re: CYA Testing

    If you go to the pool calculator, you first input your pool size in the "Size" box, up near the top, by the "Calculate" button. Then you go down to the "Effects of adding chemicals" section and input the number of ounces of the chemical you are adding (4 pounds = 64 ounces weight), and choose "dichlor". Then hit the calculate button, and the effect will show up in the box.

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    Re: CYA Testing

    Quote Originally Posted by Butterfly
    What is the water temperature? Did you warm the sample to room temp before testing?
    What is room temp considered to be? To clarify if I want to check my cya and the pool temp is 60deg what should be done? I've never let anything warm up before.
    DONE, 20 x 40, inground gunite, 30" raised bond beam with 3 12" sheer descents, 8' diving board, pentair 420 cartridge filter, vs-3050 pump, intellechlor ic-40, auto cvr, Tahoe blue pebble tech, 6ea 4' x 12.5' & 2ea 1' x 12.5' helicol solar panels, legend robotic cleaner.

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    Butterfly's Avatar
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    Re: CYA Testing

    Quote Originally Posted by bobby1017
    Quote Originally Posted by Butterfly
    What is the water temperature? Did you warm the sample to room temp before testing?
    What is room temp considered to be? To clarify if I want to check my cya and the pool temp is 60deg what should be done? I've never let anything warm up before.
    Well, the CYA test is more reliable when you let the sample warm up to room temperature first. For my purpose of "room temp", I just say to knock off the chill and 60ยบ is chilly. Some of us just pull the sample and drop it in a cup of warm water to knock off the chill. Doing this first and allowing it to sit while you do the other tests gives it time to warm up a little before testing, which will make your testing more accurate. The CYA test is +/- 15 under normal conditions.

    Hope this helps.
    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.

    ~ One should not use a sledge hammer to swat a mosquito. ~

    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  10. Back To Top    #10

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    Re: CYA Testing

    Thanks for the clarification. I'll try that on my next test.
    DONE, 20 x 40, inground gunite, 30" raised bond beam with 3 12" sheer descents, 8' diving board, pentair 420 cartridge filter, vs-3050 pump, intellechlor ic-40, auto cvr, Tahoe blue pebble tech, 6ea 4' x 12.5' & 2ea 1' x 12.5' helicol solar panels, legend robotic cleaner.

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