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Thread: CYA levels are high

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    CYA levels are high

    Hello and again thanks for the fine advice; I have saved so much by following this Forum methods rather than the "recommendations" from the Pool Store Supplies.
    This just started happening, my CYA levels are high, 110.
    Here are the measurements from today on a 18,000 gallon, plaster inground pool:
    Ph 7.6
    TA 90
    CYA 110
    Cl at or less than 1

    I have used "Pool Time" powder which lists Sodium Dichlor as 99% of the content, and had good results, crystaline water. Yet in the last few weeks, my CYA readings are high and Chlorine levels very low.
    I am in Southern California, where water is not cheap, and although not a Scrooge I will drain, about 2 feet of water and replace from the faucet, rebalance and see what happens. AND stay away from the dichlor.

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    dandjpool's Avatar
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    Re: CYA levels are high

    Trust me when I say you are better off just draining the necessary amount of water and getting it over with: http://www.poolcalculator.com/

    I just drained and filled approximately 50% of the water in my pool and rechecked my CYA levels and it was still 60ppm. I added 2.5 gallons of 6% bleach and it didn't even register at 1ppm on a chlorine test. I finally bit the bullet and did another 50% drain and measured the CYA at 30-40ppm and added 1 gallon of bleach and the chlorine has held steady at about 3-4ppm for about a week now.
    If you only drain 25% of your pool (or whatever 2 feet may be in your pool) you will be fighting to keep the chlorine on target: pool-school/chlorine_cya_chart_shock

    This is the second time I screwed the CYA levels up beyond belief with dichlor and the second time I came to TFP hoping somebody would tell me something different than what I already knew and the second time I did a 50% & 50% drain. It sucks, I know.
    I'm done with the **** dichlor too.
    Pool configuration:
    20K Gal inground vinyl liner-1 skim 1 main 2 return
    hayward c3000 cart. filter
    hayward northstar 1.5hp pump
    hayward 250k btu heater
    polaris watermatic G1000 chlorine feeder
    polaris c-300 orp controller
    Polaris 380 with booster
    aquamatic hydraulic pool cover

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    Re: CYA levels are high

    Have your CYA retested at three dilution levels. Make a sample to be tested consisting of the following ratios of pool water to tap (or distilled) water.

    Pool water......Tap or distilled water.........Multiply result by

    ....1...................1................................2
    ....1...................2................................3
    ....1...................4................................5

    The results should be close, and will give you a better idea of what your level really is. Anything over 100 cannot be reliably measured by doing the test without dilution. Even with dilution, the test will be only a reasonable approximation.

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    duraleigh's Avatar
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    Re: CYA levels are high

    Ph 7.6
    TA 90
    CYA 110
    Cl at or less than 1
    Welcome to the forum. Of course, I think you recognize that your CYA is too high but do you also see that your FC is W-a-a-a-y too low? For a CYA of 100+, your FC needs to be KEPT at 8-12ppm never letting it go below that.

    Bite the bullet and drain/refill until you get your CYA down to 50.....then you can manage your pool.

    Meanwhile, get enough chlorine in your pool to prevent Algae....I would bring it up to 10ppm. What does your water look like?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: CYA levels are high

    Wow, my own thread!
    Thank You All.
    @Duraleigh, I tried to raise my free chlorine, and that's when the problem started. Adding the Sodium Dichlor gave reading of FC 8ppm or higher, good. Within 2 days it was 2ppm, three days less than 1ppm. Continuing with more dichlor seems to be what caused the rise in CYA and immediate, almost, drop in FC.
    The water looks clear, i can see every corner and bottom of the pool, but the walls and floor are beginning to look green.
    So I will proceed with the drain, might as well backwash the filter. Whoa 50% they recommend to drain it, I'll do it.

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    Re: CYA levels are high

    Yes, dichlor was the cause of raised CYA. You should raise your FC with bleach from here on out.

    Also, the walls and floors beginning to turn green indicate that a shock will likely be needed. Do NOT try to shock while you have high CYA though...you will never be able to keep enough FC in there for shock level. I would drain/refill as soon as you can, so you can start to enjoy pool season!!

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    Re: CYA levels are high

    I just did a 50% drain for the same reason. I shocked with 4 large bottle of bleach and my swam cleared up and turned blue literally over night. And it was really a swamp! You could not see the bottom or sides of the pool! It is amazing what bleach can do when CYA isn't TOO high. I'm in So Cal too
    10,000 gallons Splash Pool; cartridge filter; vinyl; AG; pump Sta-Rite 1 HP

  8. Back To Top    #8

    Re: CYA levels are high

    SUCCESS...!
    I did the 50% drain, with the added bonus of the kids on my side of the street having a good time splashing their feet in the - clean - runoff. That went on for some hours.
    After the lengthy refill, my reading for CYA is about 60. With clean filter, and just 2 gallons of bleach, like horsegal said, overnight went from bleh! to blue and clear.
    If it's OK to mention brands a got the Kem-Tek liquid, chlorine at 10% for $7 in the 2 gallon pack.

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    Re: CYA levels are high

    Very nice! Maintaining your FC from here on out will be much easier!

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