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Thread: Zero chlorine and Very high CYA and CH

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    Zero chlorine and Very high CYA and CH

    I have a 15,500 gallon inground plaster pool. I recently purchased the taylor 2006 kit. Doing the tests, this is what i got.

    FC 0 (the reason for the 0 chlorine is, we recently purchased the house and prev owners didn't seem to have added any chlorine during the 3 weeks period. Only trichlor jumbo tabs were used as i could tell from the floater and trichlor bucket that we left behind.)
    CC 0
    PH 7.5
    Total Alk 180
    CH (using the taylor 2006 kit, at 10ml, it took 22 drops). So 22x25 = 550
    CYA (it's way below the 100 mark on the test tube) It's on the 1 1/2ml mark on back of the tube which i would say more like 300 cya. I can't tell exact measurement since tube is not labeled below the 100 mark.

    I added half gallon (10% liquid chlorine) but i still can't read any chlorine on the kit. I'm guessing it's because of high CYA.
    Water look clear. No signs of cloudiness or algea.
    What do you suggest i do at this point. How come the water still looks good even though no chlorine in water and high CH. What do i adjust first at this point and how do i get free chlorine up to it's proper level 3-4ppm.

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    Join Date
    May 2007
    South Central NJ

    Re: Zero chlorine and Very high CYA and CH

    You will need to dilute the water to lower the CYA to a manageable level.

    The Alk and CH are pretty high and scale formation is likely. CH is like CYA in that it doesn't go away without diluting.

    Check your fill water for CH. It may be high to begin with so this will become an ongoing concern.

    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    In the Industry

    duraleigh's Avatar
    Join Date
    Apr 2007
    Sebring, Florida

    Re: Zero chlorine and Very high CYA and CH

    Hey Alex,

    Welcome to the forum Yeah, your first decision is to reduce your CYA. It is at an unmanageable level and will make pool maintenance problematic.

    Assuming you live in an area where the water is not too expensive, drain half of your pool and refill. Test CYA and then plan on doing another 50% drain. You are looking to get your CYA down around 50ppm which could mean 3 possible drains.

    While it's not very accurate, Test CYA again by using 1/4 pool water, 1/4 tap water and 1/2 R-0013 reagent. Then double the visual result and you may get a somewhat more accurate idea of your current level.

    Regardless, anything over 100 is really too high to do a good job taking care of your pool.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Butterfly's Avatar
    Join Date
    May 2007
    South Carolina

    Re: Zero chlorine and Very high CYA and CH


    Where are you located, city and state?

    Your pool may be a candidate for an RO treatment (reverse osmosis for pools) which is available in limited areas of the country.

    Otherwise, what Dave & Scott said is the only other option - to do a drain/refill dance to lower the CYA & CH.

    It would be helpful if you add your pool and equipment specs to your sig.
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  5. Back To Top    #5

    Re: Zero chlorine and Very high CYA and CH

    Thanks for your replies. I live in california. Water here is expensive. How about if i shock the water with high level of chlorine, would that lower cya or balance it. If yes, how many gallons of 10% chlorine do i need to dump in. If not, then i'll have no option but to partially drain and refill the pool. Water looks sparkling clean even though clorine is 0 for the past 2 weeks with high cya and ch.

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    Mod Squad zea3's Avatar
    Join Date
    Jul 2009
    Houston, Texas

    Re: Zero chlorine and Very high CYA and CH

    CYA can only be lowered through reverse osmosis treatment or by draining and refilling. With very high CYA you may need to do a series of drain and refill cycles to get the CYA to a reasonable level.

    Google "reverse osmosis pool service" to see if this service is available in your area. It would lower the CYA and CA, and you would lose very little water.
    TFP Moderator
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    Re: Zero chlorine and Very high CYA and CH

    Thank you all. I will take the step of partially draining and refilling everyday until i get to the proper cya. It's about 100 degrees in California. How high should i keep my CYA to keep chlorine in pool longer.

  8. Back To Top    #8

    Re: Zero chlorine and Very high CYA and CH

    Did you find out the cost of RO service? It may actually be a better deal, after you figure all the chemicals you will have to add to get the pool back into shape. I understand that they leave the pool chemistry perfect.
    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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