Bubbles per second doesn't really say a whole lot about CO2 levels in most cases. Tank size, flow patterns, plant types and density, surface agitation, and delivery method all work together to make every tank different.
That being said, I can't believe that 1 bubble in 30 seconds translates into any useable amount of CO2 being injected into the water. Remember that CO2 is being exchanged with the atmosphere constantly, and I don't know whether an injection rate like that could even keep up. Most of us inject something like 30-120X that much, if not more.
CO2 normalizes with the gasses in the water even across the surface of the "bubbles" so the air in the reactor isn't necessarily 100% CO2 depending on how long it's been in the water. If no bubbles escape the reactor though, you know that none of what you do inject gets wasted at least.
Don't worry too much if some air is getting out of the reactor. It's very tiny bubbles anyway, which roll around with the current, rather than shooting out of the top of the tank.