I wouldn't recommend the skimmer box. You've got a 29g tank, right? That box will fill up a larger portion of the tank than you probably want to give up. I have a 46g and bought the skimmer box for the Remora Pro. The thing is huge, plus it attaches to the skimmer pump in a pretty dumb way. It never made it in the tank.
Have you tried adjusting the skimmer cup down a little? Are you pulling out any skimmate? If you're not getting much gunk in the cup then if you adjust the cup down some it should reduce the bubbles going into the tank. Just make sure you don't adjust down too much at one time or you'll fill that cup up in no time flat. It's a delicate balance.
If you ARE getting a good amount of skimmate in the cup, then I'm not sure what to tell you.