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Thread: Where did my CYA go?

  1. Back To Top    #1

    Join Date
    Jul 2012
    Location
    Tulsa, OK
    Posts
    24

    Where did my CYA go?

    Just opened the pool this weekend. 23,700 gallon above ground. Vinyl liner. Sand filter.

    Current readings:
    FC 3.5
    CC 0.5
    PH 7.5
    TA 100
    CYA <30

    The CYA level was between 50 & 60 when I covered the pool last fall. I expected it to be about the same when I reopened. My test cylinder only reads to 30 and the dot on the bottom is still visible when the vial is full. My CYA level is likely closer to 20.

    I didn't think this stuff went away. Reopening the pool required a <10% fresh water add. What could have caused the acid level to drop so dramatically over the winter?

    Thanks,
    BtBO
    Thanks for reading... - Tony
    Da' Pool: Intex 15'x42" 3284gal AGP EasySet (Inflatable Ring) - (Summer 2014: 27' round EW /w 6.5' deep end @ 22,500gal)
    Pump & Cart Mod: 1000gph Cart. 5ft² - 2 nylons, 24/7 OP. Traps bugs/bits, lasts longer/cleans easier = Happier Pool Owner!!
    The Bible for a "Trouble Free Pool" life = PoolSchool, the BBB method a TF100 test kit(Recommend Kits Compared). - Cleaning a Sand Filter
    Water looks like GLASS, if yours doesn't...SLAM IT! Feels nice and never been happier!!! :D

  2. Back To Top    #2

    Join Date
    Jun 2013
    Location
    Manteca, CA
    Posts
    18

    Re: Where did my CYA go?

    Bacteria eats CYA and converts it to ammonia. Cheap aquarium test kit will show if you have ammonia in your pool. Other than that, splash out explains the rest of the loss. Simple fix is to add more of it.
    In-Ground Gnite Pool (unknown build date)
    Sta-Rite 3 - OEM Filtration Cartridge
    Pentair VS + SVRS Pump
    Poolvergnuegen 2X Suction PoolCleaner (1st Gen)
    Solar Heater on 2-Story House (unused/no solar controller)

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    duraleigh's Avatar
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    Apr 2007
    Location
    Sebring, Florida
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    30,085

    Re: Where did my CYA go?

    Splashout and rainwater can usually account for most of the loss.

    I would suggest calculating and adding enough to get to 20-30 ppm. You do not give your location (city and state, please) but that should put you no higher than 50 ppm total which is good for most regions.

    Ammonia should not be a concern since you are holding some chlorine in the pool.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4

    Join Date
    Jul 2012
    Location
    Tulsa, OK
    Posts
    24

    Re: Where did my CYA go?

    Quote Originally Posted by duraleigh View Post
    Splashout and rainwater can usually account for most of the loss.

    I would suggest calculating and adding enough to get to 20-30 ppm. You do not give your location (city and state, please) but that should put you no higher than 50 ppm total which is good for most regions.

    Ammonia should not be a concern since you are holding some chlorine in the pool.
    Thanks for the info. I'm in Tulsa, OK.

    This is my 6th summer with this pool and I've never added any stabilizer since it was initially filled. I float some pucks for a couple of weeks while on vacation and that's always been enough to keep the CYA up to the 50 or so range through the summer.

    That's why I was surprised this week as it's never been below 30 before.
    Thanks for reading... - Tony
    Da' Pool: Intex 15'x42" 3284gal AGP EasySet (Inflatable Ring) - (Summer 2014: 27' round EW /w 6.5' deep end @ 22,500gal)
    Pump & Cart Mod: 1000gph Cart. 5ft² - 2 nylons, 24/7 OP. Traps bugs/bits, lasts longer/cleans easier = Happier Pool Owner!!
    The Bible for a "Trouble Free Pool" life = PoolSchool, the BBB method a TF100 test kit(Recommend Kits Compared). - Cleaning a Sand Filter
    Water looks like GLASS, if yours doesn't...SLAM IT! Feels nice and never been happier!!! :D

  5. Back To Top    #5
    Scuba_Steve's Avatar
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    May 2015
    Location
    Pooler, GA
    Posts
    311

    Re: Where did my CYA go?

    Quote Originally Posted by Babe the Blue Ox View Post
    Thanks for the info. I'm in Tulsa, OK.
    Please add this information to your profile.

    It shouldn't just go away, but sometimes stuff just happens that we can't explain. Just get it back in there!
    6425g Intex Ultraframe 18'x48" AG
    Stock 1500gph cartridge filter / Intex SWG CG-28669 with E.C.O.
    Install date: 5/26/2015
    TF-100
    Helpful Links

  6. Back To Top    #6
    Mod Squad kimkats's Avatar
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    Tallahassee, FL
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    Re: Where did my CYA go?

    Mine loses CYA over the winter as well. I really think mine is from the draining and refillingI have to do when it rains.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

  7. Back To Top    #7

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    Jul 2012
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    Tulsa, OK
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    Re: Where did my CYA go?

    Quote Originally Posted by Scuba_Steve View Post
    Please add this information to your profile.
    Done. How do I remove or update the signature. None of that info is mine.

    Stabilizer is dissolving in the pool now.

  8. Back To Top    #8
    Mod Squad kimkats's Avatar
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    Re: Where did my CYA go?

    Here ya go!

    Pool School - Getting Started

    This shows how to fill in your info.

    Kim
    TFP Moderator 33x52 round AG 25,600 gals Sand Filter 1.5hp Pump - 2 Speed, SLAM, Pool School, Recommended Levels, Recommended Chemicals, Pool Math, Chlorine/CYA Chart, TF-100 Test Kit

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