Good points Warkovision.
Considering the lack of standardization and possible lack of skill implementing Ozone in a spa, could it be possible that the gas is making its way out of the water and into the air? If the design was poor to begin with, it seems reasonable that a malfunction could put unsafe concentrations in the immediate area. I am not familiar AT ALL with ozone in a spa, so these are questions the inquiring mind needs answers to.
Perhaps someone has a link or two that would help me understand what a good spa O3 implementation was.
The initial poster's question mentioned the dealer said the O3 was possibly not working properly. What goes wrong with these devices? Other than the physical symptoms, how does one know they have a problem with their O3 generator?