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Thread: Combined Chlorine

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    tcat's Avatar
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    May 2012
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    Combined Chlorine

    Does a CC reading of "2" always mean you need to shock? I've had low CYA and adding Trichlor tabs to increase it. My FC is around 6 (only needs to be 2 or 3 at CYA 20). Could the high CC reading just be that my FC is high, or should I just shock (since shock level is so low at this CYA)? Water looks clear.
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
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    JasonLion's Avatar
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    Re: Combined Chlorine

    Yes, in your case you need to SLAM the pool. If CC is high and FC is near zero, sometimes simply raising FC to normal levels will get rid of the CC. But when FC is already at normal levels, you need to SLAM.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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  3. Back To Top    #3
    tcat's Avatar
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    Re: Combined Chlorine

    Slamming. Before slam, fc was 4, cc was 2. One hour after slam, fc was 12, cc was 0. But yeah, overnight 12 to 10. Be checking it every hour or two today.

    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

  4. Back To Top    #4
    tcat's Avatar
    Join Date
    May 2012
    Location
    Austin, TX
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    708

    Re: Combined Chlorine

    OK, passed OCLT last night. CYA was 20 (or less), so slammed to 10-12. Lost .5 last night (11 to 10.5) with zero CC (very very faint pink, so maybe .1). Today after 1" of rain and 3 or 4 hours of sun FC is down to 9 and CC is at 1. Pool is clear (and was before). I also have had Pucks going with auto feed set at 5 to raise CYA (and FC) since 7 AM, yet FC has still dropped to 9. I know that's still high, will CC go down once FC has settled at 3 or 4? I'm thinking at CYA 10-20, FC can drop pretty fast so Pucks probably aren't keeping up. Will start maintaining with Clorox at FC 4 (or after CYA = 40 if Pucks keep up at the lower levels).

    Edit: Did "reverse" oclt last night to see how much fc the pucks were adding. Went from 6.5 to 8.5 in 12 hours. So I can translate that to 4 power day from 10 pucks. Hopefully adding about 2 day per day. May buy some stabilizer to speed things up.
    IG pebble, 15,000 gallon
    48 PentAir DE Filter with backwash valve
    PentAir Whisperflo pump with 1hp 2-speed motor
    Aquabot 4WD, Poolskim
    Intermatic Dual Timeclock with freezeguard
    DIY chlorine feed
    BBB

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