Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: CC questions - is some CC eliminated without shocking?

  1. Back To Top    #1

    CC questions - is some CC eliminated without shocking?

    Is shocking the only way to get rid of of combined chlorine, or can the normal addition of chlorine for general chemical balance eliminate small amounts of CC? In my pool, my CC is almost always 0 (i.e. not detectable using a Taylor FAS-DPD kit.) Every once in a while, however, I get a very low reading of around 0.2 ppm. After my normal dose of chlorine, my tests go back to showing 0 CC. Does this indicate that the small amount of CC was actually eliminated, or does it point to a small variation or error in the testing process?

    I do know that during the FC test, the water can sometimes appear clear when it's still just barely pink. I'm careful to make sure that the water goes ALL the way to clear during the FC test, with NO residual pink, without adding any extra reagent.

    On that note, does the addition of an extra drop of reagent during the FC test throw off the CC test? There are many times when the water seems REALLY close to clear, but not quite, so I add another drop. Usually I can see it clear up that last little bit, confirming the need for the last drop, but once in a while I feel like that last drop may not have been needed. It seems like this extra drop of reagent would cause the following CC test to be off by one drop because the first drop of the other reagent is "already there." Does the test work this way, or do the chemicals react in such a way that an extra drop during the FC test will not effect the subsequent CC test?

    Thanks,

    Larry
    Los Angeles, CA -- 22K gallon in-ground plaster pool with spa, built around 1980, replastered around 2009-2010.
    Pentair Intelliflo VS (variable speed) pump and Quad 100 DE filter. Older "MiniMax" gas heater. Pentair Rebel cleaner.
    NO SWG - Liquid Cl only. Taylor K-2006 test kit.

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    9,090

    Re: CC questions - is some CC eliminated without shocking?

    Sunlight eliminates CC as well. Don't worry about anything less than 0.5ppm.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

    Join Date
    Jul 2010
    Location
    England, UK
    Posts
    156

    Re: CC questions - is some CC eliminated without shocking?

    Yes, some CC will be eliminated by maintaining normal FC levels, although this can be masked if you have something lurking in the water that makes CC faster than you can bring it down. The process just goes a whole lot faster at shock level.
    90k litres, outdoor in ground pool, concrete, painted (I hate paint)
    Sta-Rite 5P2R 1.5 Hp pump, undersized sand filter (needs upgrading).

  4. Back To Top    #4

    Join Date
    Jun 2011
    Location
    Northern Maryland (near Delaware)
    Posts
    170

    Re: CC questions - is some CC eliminated without shocking?

    I had the same concern, one day it is there, then it is gone. No issues here, and I have not really needed to shock except before we got dumped on by the hurricane.
    15'X30'X52" AGP AquaSports Grande Buttress Free (10,620 Gallons), Hayward Dreamline S190 W Zeobrite, 1.5 HP Hayward PowerFlo LX, AquaLuminator Light+ fountain attachment, Pool Rover, Tf-100 test kit, Speed Stir.

  5. Back To Top    #5
    frogabog's Avatar
    Join Date
    Jul 2010
    Location
    Portland, Oregon
    Posts
    1,578

    Re: CC questions - is some CC eliminated without shocking?

    My take on CC is that it simply means your chlorine is actively working on something. If it's a small every day kind of something (dirty kids, organics, etc.) it's normal and less than .5ppm. It does it's job, the air and sunlight carries it away and then it's gone. Just like it's supposed to.

    ?? Am I wrong?
    Where kids swim in 54 degree water, turn blue, and giggle happily cuz they got a POOL!
    Year 3 BBB -15' x 48" Intex Metal Frame - Was using (2) 1000gph Intex cartridge filters (see Full time pumping Intex). 2012, converted to 1600gph and sand filter+SWG = Sand filter love affair!
    Don't waste time and energy looking for a better value on test kits, the TF100 is the best deal around. I did the looking and spent the extra money, but you don't have to make the same mistake. Just go here: TFTestkits. I use Pool Calculator for min/max, and shocking chlorine levels.

  6. Back To Top    #6

    Re: CC questions - is some CC eliminated without shocking?

    Thanks for the responses.

    Any feedback on the second question, i.e. (quoting from the first post):

    I do know that during the FC test, the water can sometimes appear clear when it's still just barely pink. I'm careful to make sure that the water goes ALL the way to clear during the FC test, with NO residual pink, without adding any extra reagent.

    On that note, does the addition of an extra drop of reagent during the FC test throw off the CC test? There are many times when the water seems REALLY close to clear, but not quite, so I add another drop. Usually I can see it clear up that last little bit, confirming the need for the last drop, but once in a while I feel like that last drop may not have been needed. It seems like this extra drop of reagent would cause the following CC test to be off by one drop because the first drop of the other reagent is "already there." Does the test work this way, or do the chemicals react in such a way that an extra drop during the FC test will not effect the subsequent CC test?


    I realize that this would only make a 0.2 ppm difference in the result (when using the 25ml sample size), but I'd still like to fully understand all the parameters here. Knowing whether or not the extra drop influences the CC test will potentially allow me to be slightly more accurate with the CC test.

    Thanks,

    Larry
    Los Angeles, CA -- 22K gallon in-ground plaster pool with spa, built around 1980, replastered around 2009-2010.
    Pentair Intelliflo VS (variable speed) pump and Quad 100 DE filter. Older "MiniMax" gas heater. Pentair Rebel cleaner.
    NO SWG - Liquid Cl only. Taylor K-2006 test kit.

  7. Back To Top    #7
    Melt In The Sun's Avatar
    Join Date
    Oct 2009
    Location
    Tucson, AZ
    Posts
    3,899

    Re: CC questions - is some CC eliminated without shocking?

    I suspect you're right about that, but I don't know for sure either. It certainly seems that any excess of the R-0871 would decrease the indicated CC.
    11,200 gal, Pebble-Tec; Tristar 2-speed 1hp - Swimclear 325 ft2 cart - SWG - A & A in-floor cleaner - Heat pump. For the poolside cooking, a Yoder Wichita and a Big Steel Keg!
    TF Test Kits -- PoolMath -- Pool School
    Make each day your masterpiece. - John Wooden

  8. Back To Top    #8

    Join Date
    Mar 2007
    Location
    San Rafael, CA USA
    Posts
    12,082

    Re: CC questions - is some CC eliminated without shocking?

    Yes, whatever amount you overshoot the FC test will result in the CC test reporting that much lower. If you stop and count at the point when the color disappears, then you'll get a result to within one drop (or 10%, when the number of drops is large -- reason being that then the sample volume errors dominate).
    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"

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •