Bubbles from return jets???

[Themacdadt]

My pool has a spa in it, I assume there is a way for it to get air for the bubbles.

My problem is that when I hook up the vacuum via the skimmer I get a few constant air bubbles coming out of one of my return jets in the pool. And hear a popping or cracking noise underwater.
Is it possible that air is getting by from the air supply to the spa? I also clog the jet with my finger for a couple seconds and release and it like burps a big air bubble. I don't think I have a leak but won't rule out a small leak. After vacuuming I disconnect the hose and it goes back to normal.in lay mans terms I feel like it can't satisfy the demand on suction through the hose and might be seeking demand from somewhere else.
Any input would be great. Also no bubbles in pump basket

 

[linen]

If it is just a few small bubbles and only when the swg is on, then that is likely your culprit...and typical (not a problem) for a swg.

If you are getting a lot of air in your pump basket, then you have a suction side leak that is causing air to go through your system. See: http://www.troublefreepool.com/pool-school/leak_detection

 

[linen]

I probably should mention that the air supply for the spa goes out into the pool/spa and will not get into the suction side typically.