Hi
I am using it upright.

The tank is fully "full" when I get it.
I have checked for leaks where the regulator connects to the tank...nothing....I have used so much soap on the tank and gauge now they are actually slippery

One thng I note is the number of bubbles.....it has been suggested that 2 bubbles per second is good to start.....well I did that and slowly started to increase the number checking to see what the fish are doing. I can get to a point were the bubble stream is actually a stream....you can't see the individual bubbles...the fish seem to be ok.....is I go too far past this they will begin gasping for air. At this stage I think the needle valve is putting out a steady flow of gas...which would drain the tank fast.

I hope this is making sense....should I just leave it at 2 per second? The difusor seems to be able to handle whatever amount I chuck at it...I can see the gas going in and nothing coming out....so I am assuming it is being absorbed.