I tried connecting the water pump from my Fluval Spec to the canister's intake... no dice there. It would push water into the canister and water would flow out, but the air pocket remained.
Finally, in one last act of desperation/stupidity I removed the top so that I could manually top it off with tank water. A fair amount of water came rushing out as I removed the top and even more while I was putting it back on.
However, this seems to have done the trick. If I dont hear any air noises in the next day or so, then I'll know for sure. In the future, I'll be sure to attempt this method in the kitchen sink.