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Thread: Where has my CYA gone?

  1. Back To Top    #1

    Join Date
    Jan 2014
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    Sydney, Australia
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    Where has my CYA gone?

    Just finished the SLAM & its all looking perfect on all the levels.

    About a month before the SLAM (2 months ago) I added CYA & it was at the upper levels 80-90.
    Tested it again & its <10!

    I've only done about 3-4 back washes, but they're only <2min & probably lost about 3" of so of water level all up.
    I thought high chlorine might throw off the test, but we're back down to FC: 6 & there's no CYA.


    How have I lost my CYA?
    (test kit is <1 month old)

    I'll grab some more, but i'm hesitant to pop more in - in such a short time frame.
    50,000L Concrete with Pebblecrete
    SWG - watermaid
    Pool is between 2 2-storey houses, so strong sunlight from 10:00-16:00 at most (1/2 the day)

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    Mod Squad zea3's Avatar
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    Re: Where has my CYA gone?

    What are you using to test the CYA? How is your chlorine consumption? What percentage is the SWG set at?
    TFP Moderator
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    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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  3. Back To Top    #3

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    Re: Where has my CYA gone?

    Quote Originally Posted by zea3 View Post
    What are you using to test the CYA? How is your chlorine consumption? What percentage is the SWG set at?
    Taylor 2006 - 1 month old kit
    good - passed the OLT 2 weeks ago, just figuring out where my SWG needs to be set with my pool - so changing the levels a bit.
    Very little debris makes its way into the pool - a manual clean every week yields very little dust/dirt/leaves. The skimmer picks up most leaves during its daily cycle, & less than 12 leaves make it to the bottom each week.

    The cell is on its way out - 6 years old & can only get 18/30 at maximum setting (g per hour *i think*)
    Spoke to the Watermaid people & i'll get another 6-12 months out of it no issues.
    Just cleaned the cell & its currently running at 12, so keeping up no issues (can go to 18 if I need to)

    only 6hrs of sun maximum a day - as its between houses, so gets a lot less direct sunlight each day.
    50,000L Concrete with Pebblecrete
    SWG - watermaid
    Pool is between 2 2-storey houses, so strong sunlight from 10:00-16:00 at most (1/2 the day)

  4. Back To Top    #4

    Join Date
    Oct 2007
    Location
    Valrico, FL
    Posts
    537

    Re: Where has my CYA gone?

    Some types of organisms "eat" CYA. SLAM does kill them. So more than likely your problem (reason for SLAMming) eat your CYA.
    7,500 gal, IG pool, L shape 22' x 15', 1.5 hp pump, cartridge filter, AquaPlus SWG/Controller, Pebble-Tec liner.

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    Sebring, Florida
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    Re: Where has my CYA gone?

    Some types of organisms "eat" CYA.
    Occasionally true but most always in a neglected pool over a longer dormant period....like months.
    I have no Idea where that CYA has gone but I will mention that you may be the third or fourth Australian posting hear with CYA loss in the middle of swim season. I have no explanation.

    It is almost never the test but there would be no harm in a Pool Store opinion. They seldom are very accurate but probably not that far off.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  6. Back To Top    #6

    Join Date
    Jan 2014
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    Sydney, Australia
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    Re: Where has my CYA gone?

    I'll setup a camera to see if one of our native killing machine animals is eating the CYA then

    Popped 1kg in the other day, so will test again to confirm levels are up - either way its <$30 so no huge concern if it walked out.
    50,000L Concrete with Pebblecrete
    SWG - watermaid
    Pool is between 2 2-storey houses, so strong sunlight from 10:00-16:00 at most (1/2 the day)

  7. Back To Top    #7

    Join Date
    Jan 2014
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    Sydney, Australia
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    Re: Where has my CYA gone?

    Tested a week after I added 1kg (about) of CYA & yep back up to 45.
    So it apperas the CYA did leave the pool during the SLAM
    50,000L Concrete with Pebblecrete
    SWG - watermaid
    Pool is between 2 2-storey houses, so strong sunlight from 10:00-16:00 at most (1/2 the day)

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