Ozonator or maybe not

[96SC]

I recently opened our tub (Hot Springs Vanguard)  and realized there were not any tiny bubbles coming from the bottom drain, which is where the ozone is entering the water.
I'm assuming my ozonator is shot or could it be something else?
There is a video on YouTube of a guy changing out a generator on a Hot Springs and it doesn't look that hard, is it?
Thanks all

[Vinny]

Bubbles should be coming from the circulation pump. My ozonator has been dead for years and I just disconnected the electrical wiring going to my controller. I'm not sure if the drain is where the circulation pump would be coming out of but the bubbles should be coming from a venturi of some sort ... Maybe there's an air bubbler (think aquarium) and that stopped working.

[Dr. Spa™ Ret.]

The ozonator is completely passive. It's just a "box" that air is drawn though. The problem is with the injection system (completely separate from the ozonator).

[Isaac-1]

My guess is a clog on the line leading from the ozonator to the venturi injector,  be careful though, a byproduct of the ozone reacting with moisture in the air over time in the tube is nitric acid, so handle with care, and don't assume the clear fluid in the ozonator tube is water.  As has been mentioned this is a completely separate issue from telling if the Ozonator is producing ozone, for that you need an ozone tester (glass tube you break and suck the output through to test for ozone, they cost about $12-$15 each), or if it is more than 3-4 years old you can just assume it is dead if it is not one of the new types with a built in indicator.  (Note you can buy Del brand ozonators that much of the industry uses for about $100, if you do you may have to replace the venturi ($20), or adapt it from a screw on connector to a hose barb style tubing connector ($3 plumbing fitting))

[clover]

If you are not getting bubbles, it is a water flow or suction problem at the venturri connection, or the check valve.  Attempt to blow air through the ozone injector line to create bubbles coming into the footwell inlet fitting. 

The ability to draw air bubbles in is directly related to the force of the "suction draw", and the unobstructed ozone line allowing air to flow freely through it, to be drawn into the plumbing system and injected as air bubbles.

[96SC]

Thanks everyone for their feedback but from the feedback I realize this is beyond my 'expertise'.  Time to call the professionals.