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Thread: Combined Chlorine

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    Join Date
    Jul 2011
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    St. Paul, MN
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    Combined Chlorine

    I am wondering if should be concerned about 0.5ppm CC in my pool. I just received my TF-100 a few days ago, and for 3 days in a row my CC has been 0.5. I only have a few days worth of data, but I believe my pool is consuming about 3ppm of FC per day, and it has been hot here: mid-90s air temps, high 80s pool water temp.

    Here is my full set of test results:
    FC - 3ppm (tested in evening before daily bleach addition)
    CC - 0.5ppm (single drop turns from pink to clear)
    pH - 7.5
    TA - 140ppm
    CYA - 32ppm
    CH - ~200ppm

    Is there any need to shock? I haven't performed the OCLT yet.
    20'x40' Oval 27,000 gallon Vinyl IG, Coverstar Auto Cover
    Hayward MaxFlo SP2303VSP, Sta-Rite PLD50 30 sq. ft. DE filter
    Rheem 266,000 btu natural gas heater
    Dolphin Nautilus Plus with Clever Clean
    TF-100 testkit w/ Speed Stir

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    Mod Squad Bama Rambler's Avatar
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    Jun 2009
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    SouthWest Alabama
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    Re: Combined Chlorine

    If your pool is clear I see nothing that indicates a need to shock. You can run the OCLT just to be sure.

    Some pools just run with a CC of .5. It may actually be less. Do you keep your pool covered?
    You could run the FC/CC test using a 25ml sample and multiply the results by .2 instead of .5.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    linen's Avatar
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    Re: Combined Chlorine

    Hey neighbor! (Lino Lakes)

    Yesterday and today sure has been a nice change of weather!

    I am not sure exactly what causes a 0.5 ppm CC reading, but it commonly happens to me. I reacted the first two times I saw it and shocked but both times passed the tests right away(see http://www.troublefreepool.com/pool-...king_your_pool).

    You might want to read up here on the Nature2 system, use the google search at the bottom of the page. Here is one example: http://www.troublefreepool.com/natur...ls-t15870.html

    Welcome to the forum!
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    St. Paul, MN
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    Re: Combined Chlorine

    Hi Linen - I have read the info on this site regarding Nature 2. I purchased the cartridge for this year before I discovered TFP, so my plan was to use the Nature 2 for the rest of the summer but not buy a new cartridge next year. Are there any drawbacks for using an already payed for Nature 2 cartridge, besides the staining potential? I am maintaing my chlorine levels as if the Nature 2 wasn't there.
    20'x40' Oval 27,000 gallon Vinyl IG, Coverstar Auto Cover
    Hayward MaxFlo SP2303VSP, Sta-Rite PLD50 30 sq. ft. DE filter
    Rheem 266,000 btu natural gas heater
    Dolphin Nautilus Plus with Clever Clean
    TF-100 testkit w/ Speed Stir

  5. Back To Top    #5

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    Jul 2011
    Location
    St. Paul, MN
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    Re: Combined Chlorine

    Hi Bama Rambler - I keep my pool uncovered. I am guessing that the CC will break down quicker in an uncovered pool?

    The pool water is clear and sparkles (at least in my opinion, being it is my first year with the pool). I will complete the OCLT just to confirm shocking isn't necessary.
    20'x40' Oval 27,000 gallon Vinyl IG, Coverstar Auto Cover
    Hayward MaxFlo SP2303VSP, Sta-Rite PLD50 30 sq. ft. DE filter
    Rheem 266,000 btu natural gas heater
    Dolphin Nautilus Plus with Clever Clean
    TF-100 testkit w/ Speed Stir

  6. Back To Top    #6
    linen's Avatar
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    Jul 2010
    Location
    Twin Cities, MN
    Posts
    8,649

    Re: Combined Chlorine

    I guess I would just remove the cartridge, though I am not aware of short term problems other than staining and green hair. Why put it in if it is not needed?

    Edit: Bear in mind, I am a bit of a minimalist
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: Combined Chlorine

    Because it will make me feel better about the $80 I spent on it...

    Also, it could be an insurance policy against an algae bloom?
    20'x40' Oval 27,000 gallon Vinyl IG, Coverstar Auto Cover
    Hayward MaxFlo SP2303VSP, Sta-Rite PLD50 30 sq. ft. DE filter
    Rheem 266,000 btu natural gas heater
    Dolphin Nautilus Plus with Clever Clean
    TF-100 testkit w/ Speed Stir

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