I recently heard that one should not buy Chlorine Dioxide in plastic bottles (such as the one I linked above) because of leaching of chemicals. And I also heard not to use citric acid as the activator, because supposedly the sources of citric acid are not pure. The man said to use glass bottles and HCl as activator. I don't know if this info is correct, or how much of a difference it makes, but I thought I'd mention it.
So Lad, maybe the more expensive one you got is better anyway. The link doesn't work, so I don't know if yours came in glass bottles. Are you still experiencing good results?
I think that the one I got is identical. I have it in plastic bottles, and I'm not too concerned about chemical leaching in such small quantities. Maybe if I drank bottled water out of plastic every day. And I do have the HCl. I think that some people are simply afraid of hydrochloric acid, and so prefer citric ... because they associate the former with extremely corrosive effects and the latter with something present in various citrus fruits. Sounds like the objections are from someone who's a diehard organic person: contamination, impure, etc. I myself am not too concerned about that in these tiny quantities, but if someone is, they could look for glass bottles somewhere.