I have a new to me tub that's pretty old but seems to work pretty good except half the jets do not seem to push air through them. I'm tempted to start by pulling off the dial from the top and checking there first but I'm worried I'll break it. I think the air intake is right below the dial because I can see a small hole but again I'm unsure. The jet on the right works good and has a kind of slight click feel to it when it reaches the off position and slightly locks it self in. While the left one has more of a free spin kind of feel and does not lock into place.
While I'm asking about air, there is also one random half inch hose that goes to a 3/8" hose. It had a check valve that broke off when I tried to remove it and I think it went to an ozonator. I plugged it up for now because water was leaking out of it. Had a thought it was related to the half of the tub without air and unplugged it while the jet was on and it seems to feed it's own smaller jet and it does provide air to that one jet as well albeit with no control. Is this supposed to always be feeding air?
The dials
Here is the hose and the small jet
