Airstone question: bubbles coming from wrong place?

In a newbie brewer freakout moment, I picked up an airstone kit and a O2 bottle last weekend (I turned out not to need it for that batch, it just took longer than I expected for visible fermentation to start... laugh it up... )

It's a kit from Fermentap that includes what looks like a sintered stainless airstone.

Earlier this week I was cooking up a yeast starter, so I decided to use the O2 kit to aerate the starter wort. When I turned on the O2 in some clear StarSan, I found that it bubbled very slowly and most or all of the bubbles were coming from a small gap near the base of the stone where it meets the fitting that attaches to the hose (indicated with the red arrow in the pic):



I'm guessing this is not normal, since pics I've seen of similar airstones have bubbles coming out all over the place, but I wanted a sanity check before I try to figure out what to do about it. Apparently you're not supposed to touch the airstone with your fingers since it will clog the pores. I carefully grabbed it with the plastic it came in and tried to twist it against that fitting and it didn't appear to be loose.

How do this compare with other folks' airstone setups out there? Any suggestions on how this thing comes apart or what I should try to get more even bubbles?

 

You might try boiling the airstone or soaking it in a solution of oxyclean or PBW to see if that helps any.

 

O2 should be coming through the stone itself, tighten the fittng with pliers. You'll have to grab the stone part to do that.