TLE041, do you happen to recall which ebay seller you got your diffuser/bubble counter from? I really like them. Regardless of what I decided to do, I want to order similar ones. I will give your Vaseline suggestion a try, in addition to applying some more force and cleaning the threads when I set up the tank.
Since you are talking about possibly shutting it off at night, I am assuming that the needle valve on the regulator allows you to completely stop co2 flow. Sailnut, can you confirm that for us?