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Thread: Where has my CYA gone?

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    Guest

    Where has my CYA gone?

    Just did AA treatment. Before AA, CYA is 40.
    After AA, CYA < 30.
    What happened to CYA?
    Here is what I added during AA treatment.
    Let CF to 0, and added Poly 60 for 8oz/10k gal
    Added 2 lb AA, and some MA to lower pH below 7.2.
    Added 2 bottles of Pink Stuff
    After 24 hours, although the improvement is not significant (maybe the stains are not so heavy even before AA),
    I added 4lb of baking soda to increase TA from 70 to 80~90.
    Added some MA to let pH stay < 7.2. (but increase quickly back to 7.4 after a couple of hours)
    Added about 1 gal 8.25% bleach to bring up FC back to 3ppm.

    The problem is the CYA is less than 30 now

    What has happened? Should I wait a couple of day to test CYA again before adding stabilizer?
    If I have to add stabilizer, can I use some leftover Trichlor pucks according to PoolCalculator to increase CYA?

  2. Back To Top    #2
    JasonLion's Avatar
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    Re: Where has my CYA gone?

    It is possible for CYA to disappear any time FC is zero, though having it happen any time other than over the winter is quite unusual. CYA can be broken down by certain kinds of soil bacteria, which are easily killed by chlorine.

    It is also possible that this is a testing error. The CYA test is not all that precise to begin with and results vary somewhat in different lighting conditions.

    Yes, using trichlor is a valid way to raise CYA, but keep in mind that it is fairly slow.
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  3. Back To Top    #3
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    Re: Where has my CYA gone?

    Quote Originally Posted by JasonLion
    It is possible for CYA to disappear any time FC is zero, though having it happen any time other than over the winter is quite unusual. CYA can be broken down by certain kinds of soil bacteria, which are easily killed by chlorine.

    It is also possible that this is a testing error. The CYA test is not all that precise to begin with and results vary somewhat in different lighting conditions.

    Yes, using trichlor is a valid way to raise CYA, but keep in mind that it is fairly slow.
    Thank you very much for your answer!
    I tested it twice today, even indoor light, I can still see the dot at 30 CYA mark
    Last week, my CYA testing was 40, and 2 pool stores also read my CYA at 40.
    So, some unusual things must have happened...
    I regretted to do the AA treatment

    As for Trichlor, ThePoolCalculator shows 8oz can increase CYA by 2.2 (15k gal pool).
    So, after I used 5 pucks (increase CYA by 11), how long should I wait to test CYA again?

  4. Back To Top    #4

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    Re: Where has my CYA gone?

    I believe with tablets CYA shows up basically right after they dissolve.
    John
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    Richard320's Avatar
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    Re: Where has my CYA gone?

    Quote Originally Posted by snuzxj
    As for Trichlor, ThePoolCalculator shows 8oz can increase CYA by 2.2 (15k gal pool).
    So, after I used 5 pucks (increase CYA by 11), how long should I wait to test CYA again?
    That stuff should show up pretty quick. I'd say as soon as the pucks are dissolved you can retest.
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  6. Back To Top    #6
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    Re: Where has my CYA gone?

    Quote Originally Posted by Richard320
    Quote Originally Posted by snuzxj
    As for Trichlor, ThePoolCalculator shows 8oz can increase CYA by 2.2 (15k gal pool).
    So, after I used 5 pucks (increase CYA by 11), how long should I wait to test CYA again?
    That stuff should show up pretty quick. I'd say as soon as the pucks are dissolved you can retest.
    Sounds great.
    It seems that Trichlor is a better way to raise CYA than pure stabilizer

  7. Back To Top    #7
    Richard320's Avatar
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    Re: Where has my CYA gone?

    Quote Originally Posted by snuzxj
    Quote Originally Posted by Richard320
    Quote Originally Posted by snuzxj
    As for Trichlor, ThePoolCalculator shows 8oz can increase CYA by 2.2 (15k gal pool).
    So, after I used 5 pucks (increase CYA by 11), how long should I wait to test CYA again?
    That stuff should show up pretty quick. I'd say as soon as the pucks are dissolved you can retest.
    Sounds great.
    It seems that Trichlor is a better way to raise CYA than pure stabilizer
    It's good to top it off, but it takes too long when you're needing a lot. By the time you dissolve enough pucks to get CYA up to, say, 30, the pool will be green because the chlorine the pucks released would be gone to sunlight about as fast as it left the floater!
    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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    linen's Avatar
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    Re: Where has my CYA gone?

    Quote Originally Posted by snuzxj
    It seems that Trichlor is a better way to raise CYA than pure stabilizer
    Generally not.

    If you need to raise your cya just a little, then trichlor can help, but it also lowers ph and TA.

    If you need to raise cya a lot, then it is a bad choice since you can only add a little at a time since it also adds chlorine, lowers ph, and lowers TA.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Where has my CYA gone?

    Quote Originally Posted by linen
    Generally not.

    If you need to raise your cya just a little, then trichlor can help, but it also lowers ph and TA.

    If you need to raise cya a lot, then it is a bad choice since you can only add a little at a time since it also adds chlorine, lowers ph, and lowers TA.
    I see. But using pucks is really convenient, just put them in the chlorinator and no need to add bleach either.
    My pH raises 0.1 daily. So, I am constantly adding MA, and bring TA back after some time...

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