So I got a question for everyone: When I turn on my CF-500, primmed and everything. I am notice air bubbles in my intake hose when there isn't an airstone remotely near it....it's constant. I tried checking the connection to the elbow and hose and its a tight connection. Anyone every have that problem? Or is this a faulty filter? thanks. I have a CF 400 and everything is fine with that canister, I hear absolutely hear no noise or air bubbles in my intake hose.