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Thread: Mustard Algae and very low CYA?

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    Join Date
    Dec 2013
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    Mustard Algae and very low CYA?

    Hi,

    I neglected my pool for a bit and now I seem to have mustard algae.

    My Readings:
    FC - 7.5
    CC - 0
    PH - 7.4
    TA - 75
    CH - 550
    CYA - Less then 30

    How can you test what your CYA truly is when the test only goes to a minimum of 30? Should I ignore CYA for now and shock for mustard algae?

    Yesterday I used 4 packets of shock which probably didn't help my CH. Ugh!!

    Also, we have been having rain almost everyday for the past few weeks so its been hard to keep up with FC.
    Circa 1997 35k IG free form plaster pool with attached spa, Purex-Triton 3 HP Pump, Purex-Triton FNS 60 DE Filter, Polaris 280

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    Azgirl71's Avatar
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    Re: Mustard Algae and very low CYA?

    Are these numbers from one of the recommended test kits?

    No more powder shock for you. You say your CYA is less than 30. Try putting info in pool math and shoot for a target of 30. Add granular Stablizer to a sock and set it in your skimmer or tie it in front of a return jet. Since we don't know how below 30 you are then only do 1/2 of the recommended amount.

    - - - Updated - - -

    Once you add the stablizer do not back wash for at least 48 hours. Right now set your target for 10ppm FC and keep it there the best you can.
    Lisa
    Intex AG vinyl 15' x 48" 4,300 gallons due to skimmer install, Krystal Clear SF pump combo 2800 GPH, Krystal Clear SWG, Pool Blaster Max vacuum, Hayward thru the wall skimmer, TF 100 test kit with speed stir, K 1766 Taylor salt test, My SLAM Process

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    Richard320's Avatar
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    Re: Mustard Algae and very low CYA?

    Quote Originally Posted by txpoolgal View Post
    Hi,

    I neglected my pool for a bit and now I seem to have mustard algae.

    My Readings:
    FC - 7.5
    CC - 0
    PH - 7.4
    TA - 75
    CH - 550
    CYA - Less then 30

    How can you test what your CYA truly is when the test only goes to a minimum of 30? Should I ignore CYA for now and shock for mustard algae?

    Yesterday I used 4 packets of shock which probably didn't help my CH. Ugh!!

    Also, we have been having rain almost everyday for the past few weeks so its been hard to keep up with FC.
    Are you sure the "shock" was Cal-hypo? Sometimes it's Dichlor or Trichlor, which add CYA and lower pH.

    If the CYA sample gets cloudy but the dot never goes away completely, you have some CYA. Make your best guess and use that as the Now and add enough stabilizer to get to 30. Then go ahead and consider your CYA to be 30 already as it's dissolving and start the SLAM process. When you pass the three tests, then take it up to Mustard shock level for 24 hours. By the time that's all done and the FC has drifted down to below 10 where you can run all the tests again, you should have a decent CYA reading and can continue to raise it to whatever you need.
    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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    Join Date
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    Re: Mustard Algae and very low CYA?

    Quote Originally Posted by Azgirl71 View Post
    Are these numbers from one of the recommended test kits?

    No more powder shock for you. You say your CYA is less than 30. Try putting info in pool math and shoot for a target of 30. Add granular Stablizer to a sock and set it in your skimmer or tie it in front of a return jet. Since we don't know how below 30 you are then only do 1/2 of the recommended amount.

    - - - Updated - - -

    Once you add the stablizer do not back wash for at least 48 hours. Right now set your target for 10ppm FC and keep it there the best you can.
    Yes, the test kit I use is the Taylor K-2006.

    Thanks for the advice!

    - - - Updated - - -

    Quote Originally Posted by Richard320 View Post
    Are you sure the "shock" was Cal-hypo? Sometimes it's Dichlor or Trichlor, which add CYA and lower pH.

    If the CYA sample gets cloudy but the dot never goes away completely, you have some CYA. Make your best guess and use that as the Now and add enough stabilizer to get to 30. Then go ahead and consider your CYA to be 30 already as it's dissolving and start the SLAM process. When you pass the three tests, then take it up to Mustard shock level for 24 hours. By the time that's all done and the FC has drifted down to below 10 where you can run all the tests again, you should have a decent CYA reading and can continue to raise it to whatever you need.
    Yes, the shock was 58% Cal-hypo. Thank you!
    Circa 1997 35k IG free form plaster pool with attached spa, Purex-Triton 3 HP Pump, Purex-Triton FNS 60 DE Filter, Polaris 280

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