My Rena xp3 is sending little teeny bubbles into my tank. There were air surges occuring also, so I took everything apart, and made sure that everything is connected properly and restarted. I don't see the air surges but there seems to be an almost steady stream of really really small bubbles. It almost looks like the water is dusty. I don't know if it's my imagination or not but it seems to be a little louder too. Any ideas?
Sounds like air is trapped in the unit. I'm not farmiliar with the design of the XPs but on my Cascade there is a priming "button" on the top. When air gets trapped I just press the priming button repeatidly until the air bubbles stop.