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Thread: Bromine - chlorine shock - bromates?

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    Join Date
    Apr 2016

    Bromine - chlorine shock - bromates?

    Hi Chem Geek,

    Below is an excerpt from another site. I suspect your reply was in the context of a swimming pool. I do not know if the same discussion applies to a spa. I have hightlighted your comments in red below. My questions are for a spa.

    QUESTION 1: Will shocking a BCDMH, bromine sanitized spa with sodium hypochlorite, chlorine create bromate?

    QUESTION 2: Since BCDMH already contains chlorine are you recommending/suggesting KMPS is a better choice for shocking a bromine spa?

    Bromates: Most discussions mention the bromate carcenogenic concern for drinking water and question skin absortion rates. My question/concern is breathing warm moist air that contains bromates while in a spa.

    I truly appreciate the opportunity to ask questions. For me this is about safety first, then the convienece/work to maintain the spa followed by the enjoyment of useage.

    Thank you.

    Moderator note: The copyright material from another site was removed

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    cowboycasey's Avatar
    Join Date
    Jul 2013
    Fletcher, OK

    Re: Bromine - chlorine shock - bromates?

    Welcome to TFP

    Chem Geek has taken some time off

    He is the leading person on this type of question, we have some others that may be able to help..

    I am sure you have already seen this post, maybe some of it will help
    How do I use Bromine in my spa (or pool)?)
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    Mod Squad JVTrain's Avatar
    Join Date
    Feb 2014
    Central Minnesota

    Re: Bromine - chlorine shock - bromates?

    This is a good place to start. Bromate... drain and refill

    Also from chem geek in this post: Bromine vs UV Lamp: Better than Chlorine..?, cites this paper on skin absorption rates Final Report on the Safety Assessment of Sodium Bromate and Potassium Bromate The full text is pay-to-read, but from the abstract:

    Bromate was poorly absorbed, if at all, through the skin in several in vivo and in vitro studies.


    Renal cell tumors, of a type not seen in controls, were seen in male golden hamsters administered Potassium Bromate in drinking water. Potassium Bromate applied to the skin of mice or injected subcutaneously into newborn mice or rats, however, was noncarci-nogenic. The high reactivity/poor skin absorption of these oxidizing agents was considered a likely explanation for the difference between the results seen with different routes of exposure.

    Breathing moist air would fall in the region of ingestion, but not the same as drinking water with bromates in it. It would also come into play how volatile bromates are as well as actual airborne water droplets containing bromate because of vigorous spa jet operation. chem geeks opinion on that issue in this post Will Bromine used with ozone create carcinogens
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    Join Date
    Apr 2016

    Re: Bromine - chlorine shock - bromates?

    I have decided to sanitize with bromine, BCDMH, because it allows me to miss a couple of days at a time when I am away from home or the temperatures drop below -25C. Since BCDMH contains chlorine to oxidize the bromine it seems logical to shock with pool grade sodium hypochlorite (filtered and less additives than clorox). I was also told KMPS increases the pH. Given the low absorptions rates I am thinking bromates are a very low risk. After reading all of the Chem Geek's postings about chlorine, I am now questioning the aversion to shocking with chlorine that I see on most web sites. Everyone seems to be saying KMPS is the way to go but they do not say why.

    Why design BCDMH tablets with chlorine if monopersulphate is a better oxidizer? Since the bromine ions are oxidized by the hypochlorous acid does the addition of KPMS complicate the process or work in conjuction with the chlorine in the BCDMH tablets to oxidize and sanitize the hot tub. Since KMPS does not sanitize does it not make sense to use sodium hypochlorite because in addition to oxidizing the bromine it also sanitizes the dead stuff. I plan to shock after every use and based on our history the hot tub will get used every 2-3 days so the small amount of chlorine shock will be gone.

    QUESTION: Is sodium hypochlorite or KMPS the better choice to shock a spa sanitized with bromine, BCDMH? Why?

    Thank you,

    Re: Pool grade sodium hypochlorite - I could not find a pool/hot tub supplier who sold this. A local industrial supply/cleaning supplies company sells it by the 5 litre jug. I will compare the MSDS sheets to comfirm the contents before I purchase.
    Last edited by Terv; 06-04-2016 at 02:33 PM. Reason: removed based on tim5055's reply.

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    Mod Squad tim5055's Avatar
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    May 2014
    Franklin, NC

    Re: Bromine - chlorine shock - bromates?

    Quote Originally Posted by Terv View Post
    pool grade sodium hypochlorite (filtered and less additives than clorox).
    I'm going to guess a pool store told you this is what they sell? Unless you buy bleach that is "splashless", "ez-pour" or "scented" you are getting the same stuff in a bottle of bleach that the pool store has, just different percentages of sodium hypochlorite.
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