I get leaks sometimes out of the threading area of the bottle. I use aquarium silicone to seal it up, however the stuff isn't cheap. I like the idea of hot glue that was mentioned above.
I check for leaks by placing the whole setup under water in my water change bucket and blowing into the end where the gas would normally come out. If there is a leak, you will see the little bubbles streaming out of it. If the system isn't working, 99% of the time it is because of a leak.
Last edited by newms; 02-25-2013 at 10:56 PM.