ilovemykids
First of all, let me tell you all tubs need to use chlorine or some other form of a sanitizer, ozone should be treated as a secondary or additional treatment.
Yes your D1 dealer is correct, D1 uses a properly sized, upright canister to allow the ozone to off gas before it reaches the sitting area of the tub. From what I can see on the D1 site its a very good system in theory. I can't tell you if it works because I haven't seen it in action.
With regards to you question about ozone off gassing in other tubs its not really anything to worry about. Ozone as a disinfectant is a very indiscriminate killer. It will attack anything and everything it comes in contact with. That being said, ozone also has next to no residual, as it almost immediately converts back to oxygen. Most hot tub ozone generator produce very little ozone gas so I would not worry about the health effects of a hot tub ozone generator. Now I also would not stick my head over the ozone bubble stream and take a great big inhale
There has been a lot said about whether or not ozone works in a hot tub and I don't want to get into that, if you read the dead horse section I'm sure you know why :-/ For what its worth I work in the municipal water treatment industry and my tub has a ozone generator
Good luck with your search
To ALL, please lets not start the whole ozone debate, lets stick to ilovemykids question