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Thread: Chlorine keeps going to zero

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    Chlorine keeps going to zero

    Just changed to BBB, chlorine has gone to zero twice in last 5 days. What am I doing wrong? Each time I re-chlorinated according to the pool calculator. I 've had this pool for 12 years, and only other time this happened, was when the phosphates were really high. (I live under an oak forest). But tested it for phosphates today, and result was zero.

    Very frustrated! help! Gunite finish. on pool.
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Re: Chlorine keeps going to zero

    Chlorine is consumable. It disappears from exposure to the sun or doing it's job killing organics. It must be replenished on a daily basis.

    If it is diappearing faster than you expect, you may have ZERO CYA or you may have the beginnings of algae in your pool.

    Can you post a set of current test results?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Chlorine keeps going to zero

    Sure. Temp: 84. Normally, in the past, I have shocked it once a week, and kept chlorine tabs in pool, and this has been sufficient.

    Here are my values:
    Total Cl: 0
    Free Cl: 0
    Combined Cl: 0 (of course)

    ph: 7.6
    TA: 100
    CYA: 100
    Phosphate: 0
    I think that covers it!
    No obvious algae in the pool. Water hazy.
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Richard320's Avatar
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    Re: Chlorine keeps going to zero

    What he said ^

    Chlorine will go down. Period. Either you aren't adding enough, you don't have enough CYA so the sun is destroying it, or you have algae starting. The only way to know is by testing. Test CYA. Test FC, get it up into range, test it again before bed and then again in the morning before the sun hits it. If you have the answers to that, you'll have the answer to your question. And if you can't figure it out, post the results here and someone will interpret them for you.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Chlorine keeps going to zero

    Okay. I'll do that. But with the CYA 100, I'm really surprised!
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Re: Chlorine keeps going to zero

    I'm gonna guess just a little but I suspect your CYA level has gotten so high that it has rendered your Chlorine inneffective and resulted in allowing algae (that's the haziness) into your water.

    The only permanent resolution is to drain enough of your pool water down to get the CYA back to 50ppm and then stop using the pucks as that's what has driven the CYA up too high.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Chlorine keeps going to zero

    So, with a CYA of 100, it prevents the chlorine from working on the algae? If that is true, what level do I have to get it to. I live in Fla, with days of high 90's, and nights of 80's, so I need some CYA in it. What level do you suggest?
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Re: Chlorine keeps going to zero

    The only permanent resolution is to drain enough of your pool water down to get the CYA back to 50ppm
    That's a very good starting point....you will not want to get much higher than that and you'll have to give up the pucks for the season.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Chlorine keeps going to zero

    okay. I'm glad to give up the pucks....as long as I can keep adequate chlorine level in pool. So I'll need to add bleach nightly, to keep the chlorine level, I'm guessing.
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Richard320's Avatar
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    Re: Chlorine keeps going to zero

    Quote Originally Posted by abundance56
    okay. I'm glad to give up the pucks....as long as I can keep adequate chlorine level in pool. So I'll need to add bleach nightly, to keep the chlorine level, I'm guessing.
    It's not so much work, really.

    Troublefree does not mean Maintenancefree. As I posted a few days ago in another thread: it's like brushing your teeth. You can spend a couple minutes a day for pennies a week or go to the dentist and spend several thousand dollars once a year.

    Once you get into the rhythm of things, 2-3 weeks I'll guess, you'll know pretty much before testing what you'll need to add. Grab the jug during a commercial and dump in a quart or whatever it takes. You should be looking at the pool at least once a day anyway, just to be sure it didn't spring a leak and that the pump's not screaming.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Chlorine keeps going to zero

    My husband just got home with pool test from another pool store. It says my CYA is 50. I'm going to have to buy my own CYA test kit....the one I have doesn't test it. pool store are closing here in 10 minutes. I'll check back tomorrow, after I buy a kit, as I won't be able to get to store before it closes.

    You are right, a few minutes a day, is much better than this grief every weekend! Thank you for the help! I'll let you know results tomorrow, and what I am going to do. Unreal that two different pool stores will get two such drastic result differences! ugh!
    48,000 Gallon gunite pool
    Cartridge filter. 2HP pump
    Runs 12 hours/day

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    Richard320's Avatar
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    Re: Chlorine keeps going to zero

    Quote Originally Posted by abundance56
    My husband just got home with pool test from another pool store. It says my CYA is 50. I'm going to have to buy my own CYA test kit....the one I have doesn't test it. pool store are closing here in 10 minutes. I'll check back tomorrow, after I buy a kit, as I won't be able to get to store before it closes.

    You are right, a few minutes a day, is much better than this grief every weekend! Thank you for the help! I'll let you know results tomorrow, and what I am going to do. Unreal that two different pool stores will get two such drastic result differences! ugh!
    It would be more unreal - surreal, perhaps - if two different pool stores got the same readings from the same sample!

    As long as you're going to get a test kit with CYA, you may as well go for it all and get the FAS-DPD test, too. Which means, Taylor K-2006 (Leslie's equivalent 81329) or the TF100.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  13. Back To Top    #13

    Re: Chlorine keeps going to zero

    Just to mention it, most of us here use the TF100. Great value, great service, easy to find advice here since most of us use that.
    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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