I bought this to use in my 29 biocube to replace the Coralife Biocube protein summer that wasn't doing much of anything and I've had it installed for about 5 days now (yes, trying to be patient during the break-in period) and I don't see ANY indication (0 bubbles) that it is working or going to work. Perhaps I installed it incorrectly? What is the purpose of the air tube? It isn't attached to a pump or anything? Seems like it's just hanging out, not doing anything. The air adjustment screw is all the way open. Water level is correct. Shouldn't I see something by now? Any tips, tricks, double checks are much appreciated. Thanks!!