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Thread: Where did my CYA go?

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    iggy's Avatar
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    Where did my CYA go?

    My SWG inground 12,000 gallon pool was completed in January this year. We had the CYA up to 100 ppm and all of a sudden in June the CYA tested 50 ppm on both liquid test and strips and has been that way every since. I want to maintain 80 ppm and know I need about 3 lbs of CYA to get up again to 80 ppm.

    My question where di my CYA go?
    I thought it doesn't evaporate.
    I have cleaned my filters 3 times since filling in Janauary and have only drained the pool about 2" because of rain.
    Could these things together reduced my CYA 50%?
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    frustratedpoolmom's Avatar
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    Re: Where did my CYA go?

    Do you have an autofill feature?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    frustratedpoolmom's Avatar
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    Re: Where did my CYA go?

    It doesn't evaporate. 2 inches of water - that's not that much certainly not enought reduce by half.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Butterfly's Avatar
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    Re: Where did my CYA go?

    iggy,

    When did your CYA last test at 100 and what method did you use to test?
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    iggy's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by frustratedpoolmom
    Do you have an autofill feature?
    Yes I have the automatic fill feature.
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    iggy's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by jjparrish
    iggy,

    When did your CYA last test at 100 and what method did you use to test?
    Around June 20th
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    Re: Where did my CYA go?

    My CYA disappeared since last summer also; down from 100+ to only 40 last week.

    Old fashioned pool with no automatic drainage or backwash. Nothing but rainwater, fill water, and evaporation cycles all year.

    Winters are very mild in FL; and no algae blooms since last year... so how do I account for CYA loss?
    22,000 gal in-ground, 3-8ft
    Cartridge filter
    Pebble Tec resurfaced
    Polaris 360

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    frustratedpoolmom's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by iggy
    Quote Originally Posted by frustratedpoolmom
    Do you have an autofill feature?
    Yes I have the automatic fill feature.
    You may have a slow leak....if your autofill feature is running and replacing water you could have replaced more than 2 inches....
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    iggy's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by frustratedpoolmom
    Quote Originally Posted by iggy
    Quote Originally Posted by frustratedpoolmom
    Do you have an autofill feature?
    Yes I have the automatic fill feature.
    You may have a slow leak....if your autofill feature is running and replacing water you could have replaced more than 2 inches....
    I'm 99.9% sure I do not have any leaks.
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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    frustratedpoolmom's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by iggy

    I'm 99.9% sure I do not have any leaks.
    Because?
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: Where did my CYA go?

    Going from a CYA level of 100 on June 20th (I assume this year) to 50 on July 11th in a pool with chlorine (maintaned FC level) in it seems impossible without dilution or some sort of test error. Such drops have been seen over a winter in pools that have been "let go" (presence of algae is not needed; it's soil bacteria that typically convert CYA into ammonia). So we've got a mystery here.

    If there were some sort of leak, then other water parameters would likely drop unless the fill water was high in such parameters. Calcium Hardness, for example.

    Richard
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    iggy's Avatar
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    Re: Where did my CYA go?

    Quote Originally Posted by chem geek
    Going from a CYA level of 100 on June 20th (I assume this year) to 50 on July 11th in a pool with chlorine (maintaned FC level) in it seems impossible without dilution or some sort of test error. Such drops have been seen over a winter in pools that have been "let go" (presence of algae is not needed; it's soil bacteria that typically convert CYA into ammonia). So we've got a mystery here.
    If there were some sort of leak, then other water parameters would likely drop unless the fill water was high in such parameters. Calcium Hardness, for example.

    Richard
    I'm still scratching my head on this one. I usually test weekly after the pool was filled then every two weeks. I did most of thests but followed up at Leslie Pool store which usually validated my reading. I have a feeling I will just have to leave this as unsolved and just add my my 3 lbs of CYA and move on.

    Thanks everyone.
    In-Ground SWG pool 11,000 gal., Jandy CL460 Filter, 1.5hp Stealth Jandy pump, Paramount PV3 In-Floor cleaning sys., Goldline SWG, Hayward Color Logic 2.5 LED Light

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