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Thread: Chlorine Loss

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    Join Date
    May 2010
    Location
    Mountain View, Arkansas
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    64

    Chlorine Loss

    I finally have my pool balanced and clear. The only piece of the puzzle I am missing is the correct CYA number. A few days ago I put in approximately 4 lbs of stabilizer. I put it in the skimmer, but ended up backwashing for a few minutes the next day. My CYA registered 0 when I tested it for the first time after opening the pool. I closed the pool with about 50 ppm CYA in the winter. So I assume there is residual CYA left over and I am truly not at zero. I finally did the overnight FC drop test and started out at 18.5 FC after sundown. The next morning before any sun hit the water I still had 18.5 FC and zero CC's. Yaay. So outta curiosity, I didn't add anymore chlorine all day. After the sun went down my FC dropped to 2.5 with the sun being on it for about 13 hours. So I am assuming that since I passed the overnite FC drop test, the only thing that burned the chlorine was the sun. Since I really don't know my CYA level and been assuming 30 for the moment, is the 16.0 ppm FC drop normal or do I need to assume I still have low CYA level of maybe 10 or 15 and add a couple pounds more stabilizer?

    Also my father in law mentioned chlorine granules and using them to make my own chlorine. Said it is something he used to do when he was younger and I could possibly save money making my own. Since I have never heard of it mentioned here I am thinking that this isn't the way to go. But I had to kill his curiosity.

    Thanks again for all the help.

    Al
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

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    Join Date
    Mar 2007
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    San Rafael, CA USA
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    Re: Chlorine Loss

    Let's figure that the 13 hours is equivalent to around 8 hours of direct noontime sun (it might be somewhat more, but let's just use this). Your chlorine dropped by x8 = 2.5/18.5 so x = 0.78 so 22% per hour. If you had absolutely zero CYA in the water, then it would drop around 50% per hour, so it sounds like you've got around 10 ppm CYA in the pool right now. So yes, why don't you figure on around 15 ppm so as not to overshoot.
    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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    JasonLion's Avatar
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    May 2007
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    Silver Spring, MD
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    37,879

    Re: Chlorine Loss

    You can make "bleach" out of dichlor or cal-hypo by mxing with water. You aren't making chlorine, just converting solid chlorine, which is easy to carry, into liquid chlorine which is convenient to use around the house.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Join Date
    May 2010
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    Mountain View, Arkansas
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    64

    Re: Chlorine Loss

    Quote Originally Posted by chem geek
    Let's figure that the 13 hours is equivalent to around 8 hours of direct noontime sun (it might be somewhat more, but let's just use this). Your chlorine dropped by x8 = 2.5/18.5 so x = 0.78 so 22% per hour. If you had absolutely zero CYA in the water, then it would drop around 50% per hour, so it sounds like you've got around 10 ppm CYA in the pool right now. So yes, why don't you figure on around 15 ppm so as not to overshoot.
    Thank you very much. I will shoot for an additional 15ppm. And test again in about a week.
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

  5. Back To Top    #5

    Join Date
    May 2010
    Location
    Mountain View, Arkansas
    Posts
    64

    Re: Chlorine Loss

    Quote Originally Posted by JasonLion
    You can make "bleach" out of dichlor or cal-hypo by mxing with water. You aren't making chlorine, just converting solid chlorine, which is easy to carry, into liquid chlorine which is convenient to use around the house.
    Ill just stick with the 6% liquid bleach. Thanks much
    Mountain View, Arkansas, 23,000 gallon in-ground concrete pool with a 24-in Hayward Pro-Series Sand Filter with side-mount. Chlorinator is attached but only use occasionally and a 1 hp pump.

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