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Thread: Right amount of CYA

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    jefeyessica's Avatar
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    Right amount of CYA

    We recently refilled our pool, and after reading all over the forum, I still don't know the ideal level of CYA I should have. We live in Texas, and the pool has direct sunlight all day. I don't have a SWG, so the pool calculator suggests 30-50. However, since we do have direct sunlight, does that mean I should have higher levels, around 70-90?
    My current level is around 30, and I would hate to raise the CYA level, and then having to drain the pool again. Should I just stick with 30?
    I currently add about 6 cups of 6% bleach every day (in our 14,000 gallon pool). Is this a normal amount, or is that high? I am also planning on adding borates, which should reduce the need for chlorine.
    So.... should I keep my CYA at 30, or add more??
    14,200 gallon in ground Plaster Pool
    "Titan Vertical Grid Filter" -- Pressure DE, 60 sq ft filter area

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    Re: Right amount of CYA

    I've read before that with direct sunlight all day, a slightly higher CYA works a bit better at minimizing chlorine loss. All the way to 90 seems too high to me, but 50 - 70 should be fine. You understand the relationship between CYA and FC, so you are way ahead of the game. And there won't be a need to drain the pool again, as the CYA will gradually fall with rainfall, splashout, etc.

    Enjoy!
    28K IG Vinyl lined pool - 1 skimmer, 2 returns
    Hayward DE 60sqft filter; Polaris 280 vacuum with booster pump

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    frustratedpoolmom's Avatar
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    Re: Right amount of CYA

    Go higher - at least 50. Thats alot of bleach.
    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: Right amount of CYA

    Every pool is different, so a solid number can not be given for your particular pool

    What I would do is raise the cya by 10 ppm per week until you have the 'optimal' level for your pool 8)

    As you know, cya doesn't just disappear (usually ) so bump it up, but do so in small enough doses that if you 'overshoot' a little, it's not going to cause you to have to drain water
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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    duraleigh's Avatar
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    Re: Right amount of CYA

    With the margin of error in the CYA test kit, 10ppm is frequently difficult to detect.

    I would calculate carefully (post on the forum if you have any doubts) and increase the CYA by 20ppm (it should be 2 pounds)....that should get you around an ideal 50ppm.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Right amount of CYA

    I notice that with my CYA at current 40, the goal is 3 to 7 ppm FC, and it takes 2 jugs (191 oz) of 6% chlorine to do that.

    AND

    If my CYA were 50, the goal is 4 to 8 ppm FC, and it takes 2 jugs (191 oz) of 6% chlorine to do that.

    AND

    If my CYA were 60, the goal is 5 to 9 ppm FC, and it takes 2 jugs (191 oz) of 6% chlorine to do that.

    Soooooo...... If I am adding 2 jugs of bleach each time, regardless of the CYA, to go from low range to high range FC, am I going to expect that to need doing LESS often at higher CYA levels?

    I have not been super regular about testing and adding, testing every 3rd or 4th day and adding what isneeded, and so I am not yet so sure of how much CL is comsumed by my pool.
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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    Re: Right amount of CYA

    Quote Originally Posted by anonapersona
    Soooooo...... If I am adding 2 jugs of bleach each time, regardless of the CYA, to go from low range to high range FC, am I going to expect that to need doing LESS often at higher CYA levels?
    Exactly. Your rate of loss to sunlight will be slower so it will take longer to go from the high end to the low end of your range.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

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    jefeyessica's Avatar
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    Re: Right amount of CYA

    Okay, so I added 3 lbs of stabilizer, before I had a chance to read on the forum that I should have only added 2 lbs!! I hope I didn't overshoot my goal of 50!! I did some calculating, and my average bleach per day has actually been 7 cups (6%)!!! Way too much. I am excited to start seeing a difference in the amount I'll need everyday.
    14,200 gallon in ground Plaster Pool
    "Titan Vertical Grid Filter" -- Pressure DE, 60 sq ft filter area

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