Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 6 of 6

Thread: shocking to remove DBPs

  1. Back To Top    #1

    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    781

    shocking to remove DBPs

    Hello all,

    I know the company line is that shocking is not necessary for a well maintained pool, but wouldn't occasional shocks be beneficial to eradicate disinfection by products, or will a properly maintained FC take care of that?

    Thanks,
    Dave
    20K gal IG plaster pool, Manually chlorinated with 6% bleach, 1.5 HP Sta-Rite Dura-Glas II pump, Pentair FNS Plus 48 DE filter, Polaris 280

  2. Back To Top    #2
    reebok's Avatar
    Join Date
    Apr 2009
    Location
    Lakeland, FL
    Posts
    1,268

    Re: shocking to remove DBPs

    what is a disinfection byproduct?
    to answer my own question, I believe CC's are what happens when chlorine attaches and kills an invader. it is an "intermediate breakdown product" according to pool school.
    as I understand it, all pools have CC's because the chlorine is breaking stuff down. it's just usually a very very small amount. this would be why kids (or whoever) get red eyes after swimming for hours - CC exposure even though you may not be able to measure the level of CC's.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

  3. Back To Top    #3

    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    781

    Re: shocking to remove DBPs

    Quote Originally Posted by reebok
    what is a disinfection byproduct?
    Well, that is possibly an implied question within my original post. I know that many of them as CCs are burned off with normal FC levels, but aren't there more insidious chemical byproducts that are generated in a chlorinated pool? I confess I am a victim of health related newsletters and websites that throw out scare tactic propaganda that may not be reliable...
    20K gal IG plaster pool, Manually chlorinated with 6% bleach, 1.5 HP Sta-Rite Dura-Glas II pump, Pentair FNS Plus 48 DE filter, Polaris 280

  4. Back To Top    #4
    Guest

    Re: shocking to remove DBPs

    They are not a problem in outdoor pools since they are mostly broken down by UV and/or are volatile and gas off. They are a problem in indoor pools not exposed to UV and that do not have good air handlers, particularly when there is NO CYA present.
    Normal FC levels normally take care of them in outdoor pools. If you have them they will show up as CC.


    Quote Originally Posted by Beez
    I confess I am a victim of health related newsletters and websites that throw out scare tactic propaganda that may not be reliable...
    A little bit of fact mixed with some omission of facts and misinformation from these "Health" websites leads to this type of confusion. Once you get the facts it all becomes much clearer. I bet not one of them mentioned that this is primarily a problem in indoor pools with poor air handlers.

  5. Back To Top    #5

    Join Date
    May 2009
    Location
    Dallas, TX
    Posts
    781

    Re: shocking to remove DBPs

    Quote Originally Posted by waterbear
    They are not a problem in outdoor pools since they are mostly broken down by UV and/or are volatile and gas off. They are a problem in indoor pools not exposed to UV and that do not have good air handlers, particularly when there is NO CYA present.
    Normal FC levels normally take care of them in outdoor pools. If you have them they will show up as CC.


    Quote Originally Posted by Beez
    I confess I am a victim of health related newsletters and websites that throw out scare tactic propaganda that may not be reliable...
    A little bit of fact mixed with some omission of facts and misinformation from these "Health" websites leads to this type of confusion. Once you get the facts it all becomes much clearer. I bet not one of them mentioned that this is primarily a problem in indoor pools with poor air handlers.
    Of course not! That's not in the manual "How to Bilk a Fortune from Unsuspecting Consumers"
    Thanks for that waterbear! It has been a nagging question in the back of my mind ever since I got the pool.
    20K gal IG plaster pool, Manually chlorinated with 6% bleach, 1.5 HP Sta-Rite Dura-Glas II pump, Pentair FNS Plus 48 DE filter, Polaris 280

  6. Back To Top    #6

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

    Re: shocking to remove DBPs

    Just remember that shocking does nothing more than increase the concentration of chlorine, so this would increase the chemical reaction rate for any reactions in which chlorine participates. That's all. There isn't any "magic" level at which point all of a sudden things start to happen. It's simply a continuum.

    The concept of "breakpoint" chlorination is when you are adding chlorine to water that already has ammonia in it -- in this situation, the chlorine reactions go in steps so there is, in this case, a "magic" amount of chlorine when things all of a sudden change. This is not the situation in pools, however, since you already have chlorine in the water and are instead introducing smaller amounts of ammonia (and mostly urea) into it. In other words, you already have chlorine amounts well beyond the "breakpoint" level.

    For the chlorine reaction with ammonia, the production of very irritating nitrogen trichloride is actually higher in both peak and total cumulative amounts at higher chlorine levels so in this case shocking actually creates MORE of this irritating chemical (technical details about this are here). The only time you'd need to more regularly shock is under conditions of high bather loads where the amounts of introduced contaminants to the water is at a rather high rate so you need to accelerate the reactions to stay caught up, but in this situation there are other solutions possible to assist in oxidation on a more continual basis, including ozone and UV, but again this are not needed in typical residential pools (and even most commercial/public pools are able to get by without such supplementation, especially if they are outdoor pools as waterbear described).

    Richard
    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
  •