Hardness Plus - Ozonators

[Levelheadsteve]

I just filled the tub on Friday. I'm using dichlor for sanitation and mps for shock. The calcium hardness is only 70. All other readings are good. I bought some Hardness Plus, but then I noticed a warning on the back that calcium chloride, in aqueous states, can combine with ozone to make calcium bromide, which is a carcinogen. My tub has an ozonator. Am I ok to add Hardness Plus or should I add some other product?

Thanks for any advice.

[Levelheadsteve]

Where's chem geek when you need him? 

[chem geek]

That makes no sense at all.  First of all, where would the bromide be coming from since you are using chlorine?  Secondly, calcium chloride dissolves in water to form calcium ions and chloride ions.  Ozone reacts with neither of these.  Finally, where do you find that calcium bromide is a carcinogen?  As listed in this MSDS even the solid calcium bromide product is "Not listed as a carcinogen by ACGIH, IARC, NTP, or CA Prop 65".

Now if the Hardness Plus you were using were calcium bromide (which I doubt since it's normally calcium chloride -- but check the ingredients), then ozone will oxidize bromide to bromine.  The bromine itself is not carcinogenic, but bromine combined with some organics is and these are more carcinogenic than chlorine combined with similar organics, but the amounts are relatively low.  Bromate is carcinogenic and is produced from ozone reacting with hypobromous acid but it does not absorb through the skin so you'd have to drink lots of spa water for it to become a problem.

If you give me more details about the Hardness Plus you are using, then maybe we can figure out this nonsense printed on the label.  What exactly is listed as the ingredients and their percentages?  What is the manufacturer or other parts of the brand name for this Hardness Plus product?

Also, if you have an acrylic spa then you don't need to increase Calcium Hardness unless you have foaming in which case having 120-150 ppm CH is reasonable to prevent foaming.  You don't want the CH to be too high or else you can get calcium carbonate scaling.

[Levelheadsteve]

http://i175.photobucket.com/albums/w157/levelheadsteve/image-1.jpg

I'll try to post a picture of the warning.

[Levelheadsteve]

It says it contains calcium chloride, but still has the calcium bromate (not bromide, sorry for the misinformation above) warning re: in aqueous formulations with ozone.

Regardless, with a calcium hardness of 70 straight out of the hose, should I just leave it as is since I have an acrylic tub?  Add a little calcium chloride?

[chem geek]

Ahh, now this makes more sense.

The product is primarily calcium chloride but perhaps may contain a small amount of bromide contaminant (however, this MSDS does not list any bromide).  ANY strong enough oxidizer added to the water, be it ozone, chlorine, or non-chlorine shock, can create bromine (hypobromous acid) from the bromide and this can get further oxidized by ozone (but not chlorine or non-chlorine shock) to form bromate.  It's not calcium bromate, but just plain bromate ion that is the problem and it is an EPA regulated chemical in drinking water that is a carcinogen.  As I wrote before, this isn't an issue since you are not drinking lots of spa water.  This sounds like something that was put on the bottle "just in case" or may be a mistake in labeling that was intended for a sodium bromide product.

As for your CH level, I'd leave it alone unless you notice foaming.  If you notice too much foaming, then you can increase the CH to 120-150 ppm to see if that helps.

[trichert]

It is a California only warning.  In California both H2O and O2 are known to cause cancer also   (no not really just making a jab at the ridiculousness of CA reporting laws). 

[Dr. Spa™ Ret.]

Carrots cause cancer too. No, really! They did a test, fed rats nothing but carrots for 2 years, most of them got cancer.

[Levelheadsteve]

Thank you all for the advice. I'll watch my carrot intake too.