Robo Posted January 14, 2019 Report Share Posted January 14, 2019 I have been reading on this forum a lot about hot tubs that have ozone consume more free chlorine. From what I have read, it looks like ozone reacts with hypochlorite to produce mostly oxygen and chloride but in a side reaction it also produces chlorate, an oxidized form of hypochlorite. My question is about the fate of chlorate. Does it just build up in the tub or does it go on to oxidize organic matter? Quote Link to comment Share on other sites More sharing options...
Robo Posted August 15, 2020 Author Report Share Posted August 15, 2020 Ok. Its been awhile since I asked this question so I am going to bring it back to present and see if anybody can provide a response to the initial thread. Thanks. Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted August 15, 2020 Report Share Posted August 15, 2020 Perhaps post your question in the water chemistry section of the forum for better results Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted August 15, 2020 Report Share Posted August 15, 2020 @Cusser, technical chemistry question for you. @waterbear, do you have any clue? Quote Link to comment Share on other sites More sharing options...
waterbear Posted September 11, 2020 Report Share Posted September 11, 2020 Chlorate does build up but it is taken care of by your water changes (which should be occuring regularly). It can form in any chlorine based system, not just with ozone, btw. IMHO, ozone is a better choice with bromine since it will oxidize bromide ions into hypobromous acid and that does not happen with chloride ions.Ozone can also form bromate in a bromine system. Once again, water changes take care of it. 1 Quote Link to comment Share on other sites More sharing options...
Cusser Posted September 12, 2020 Report Share Posted September 12, 2020 On 1/14/2019 at 6:22 AM, Robo said: My question is about the fate of chlorate. Does it just build up in the tub or does it go on to oxidize organic matter? Chlorate is already an oxidized form, so will not oxidize organic matter. Any chlorate formed will be eliminated when you drain your spa. 1 Quote Link to comment Share on other sites More sharing options...
PNW Soaker Posted October 2, 2020 Report Share Posted October 2, 2020 Yea ozone will create chlorate or bromate, and in Canada it is becoming law that the ozone generators say "do not use with bromine/bromide products" or something like that because of the health effects of bromate. (that's at least my understanding, could be wrong) Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted October 2, 2020 Report Share Posted October 2, 2020 3 hours ago, PNW Soaker said: Yea ozone will create chlorate or bromate, and in Canada it is becoming law that the ozone generators say "do not use with bromine/bromide products" or something like that because of the health effects of bromate. (that's at least my understanding, could be wrong) Sodium bromide granules used in conjunction with a "Bromine Generator" or salt system has been banned in Canada. Most systems being offered in Canada now are using "Dead Sea Salt" instead. https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/decisions-updates/reevaluation-decision/2018/sodium-bromide.html 1 Quote Link to comment Share on other sites More sharing options...
Robo Posted October 2, 2020 Author Report Share Posted October 2, 2020 On 9/12/2020 at 12:08 PM, Cusser said: Chlorate is already an oxidized form, so will not oxidize organic matter. Any chlorate formed will be eliminated when you drain your spa. Chlorate is an oxidized form of hypochlorite which oxidizes organic matter so why wouldn't chlorate also oxidize organic matter. When hypochlorite or chlorate oxidize something, it in turn gets reduced. So for hypochlorite, it gets reduced to chloride and chlorate theoretically would get reduced back to hypochlorite. I was just was not sure if chlorate will oxidize organic matter in hot tubs. The other question is whether ozone will go on to oxidize chlorate further to perchlorate? Quote Link to comment Share on other sites More sharing options...
waterbear Posted October 2, 2020 Report Share Posted October 2, 2020 5 hours ago, CanadianSpaTech said: Sodium bromide granules used in conjunction with a "Bromine Generator" or salt system has been banned in Canada. Most systems being offered in Canada now are using "Dead Sea Salt" instead. https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/decisions-updates/reevaluation-decision/2018/sodium-bromide.html Nice way to get around legislation. "Dead Sea Salt" has a very high bromide content!! It will still be a bromine tub! https://link.springer.com/article/10.1007/s12517-016-2431-9 2 Quote Link to comment Share on other sites More sharing options...
waterbear Posted October 2, 2020 Report Share Posted October 2, 2020 4 hours ago, Robo said: The other question is whether ozone will go on to oxidize chlorate further to perchlorate? In a word, no. "The comparative rate and efficiency of ClO4(-) production is generally greater for higher oxidation states of Cl (2.7 to 0.5% for ClO2(-)/ClO2 and 0.02 to 0.005% for OCl(-)/HOCl oxidation) with the notable exception of ClO3(-) which does not react with O3. " https://pubmed.ncbi.nlm.nih.gov/20345093/ 1 Quote Link to comment Share on other sites More sharing options...
waterbear Posted October 2, 2020 Report Share Posted October 2, 2020 4 hours ago, Robo said: Chlorate is an oxidized form of hypochlorite which oxidizes organic matter so why wouldn't chlorate also oxidize organic matter. Two words, Redox potential Both chlorate and chlorite ions have a MUCH lower redox potential compared to hypochlorite ions so they are not as effective as oxidizing agents. Chlorite ions have a redox potential that is about half that of hypochlorite ions and chlorate ions are even lower. "Table 1. Physical and chemical properties of commonly used disinfectants and inorganic disinfectant by-productsChemicalaEo (V)bOxidation number of Cl or Br8max (nm)ce (mol–1 litre–1 cm–1)dp,oepKafHOCl/Cl–+1.49+1254292 (OCl–)60419+25.27.5ClO2/ClO2–+0.95+43591250+16.1–NH2Cl–+1245416––O3/O2+2.07–2543200+35.0HOBr/Br–+1.33+133050+22.58.7ClO2–/Cl–+0.76+3262–+12.81.96ClO3–/Cl–+0.62+5360–+10.51.45BrO3–/Br–+0.61+5195–0.72aHalf-cell reactants/products.bEo = standard electrode potential (redox potential) in water at 25 °C. The oxidation–reduction state of an aqueous environment at equilibrium can be statedin terms of its redox potential. In the chemistry literature, this is generally expressed in volts,E, or as the negative logarithm of the electron activity, p,. Whenp, is large, the electron activity is low and the system tends to be an oxidizing one: i.e., half-reactions tend to be driven to the left. When p, is small, thesystem is reducing, and reactions tend to be driven to the right.c8max = maximum absorbance wavelength of that particular solution in nm.de = molar absorptivity (molar extinction coefficient), in mol–1 litre–1 cm–1. This can be used for quantitative determination of the various species of chemicalsand is the only direct physical measurement. There is often some background absorbance that may interfere with the measurement in natural waters thatshould be considered.ep,o = ! log {e–} where {e–} = electron activity.fpKa = negative logarithm of the acid ionization constant (e.g., at pH 7.5, the molar concentration of HOCl is same as that of OCl–). As this parameter isdependent upon temperature, the values listed were determimined at 25 °C" Table on page 29 https://www.who.int/ipcs/publications/ehc/216_disinfectants_part_2.pdf? 1 Quote Link to comment Share on other sites More sharing options...
RDspaguy Posted October 2, 2020 Report Share Posted October 2, 2020 Careful now, @waterbear. You keep this up and we might learn something. Quote Link to comment Share on other sites More sharing options...
waterbear Posted October 2, 2020 Report Share Posted October 2, 2020 Oh No! we certainly don't want people to understand basic water chemistry! If they did a lot of the hype and misinformation by the chemical manufacturers would be exposed! Anyone care to by some very expensive baking soda to raise your total alkalinity? We can justify the high price by calling it by an alternate name, sodium hydrogen carbonate instead of sodium bicarbonate to try and make you think they are not the same! " Sodium bicarbonate (IUPAC name: sodium hydrogen carbonate), commonly known as baking soda (especially in North America and New Zealand) or bicarbonate of soda, is a chemical compound with the formula NaHCO3 " https://en.wikipedia.org/wiki/Sodium_bicarbonate 2 Quote Link to comment Share on other sites More sharing options...
CanadianSpaTech Posted October 2, 2020 Report Share Posted October 2, 2020 4 hours ago, RDspaguy said: Careful now, @waterbear. You keep this up and we might learn something. You just make me dizzy 😵 2 Quote Link to comment Share on other sites More sharing options...
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