So I got my co2 supply this week and started trying to use it yesterday afternoon. Connected it up as per you would and hearing slight leaks tightened things up. Used soapy water to confirm no leaks I could see. So I initially set the pressure at 35PSI (ok it's slightly higher than required) to force carbonate what was already a lightly carbonated lager in the keg. I give the keg a few shakes last night to help get the co2 in the lager and as expected the pressure drops slightly. Before bed I set the pressure to 30PSI and switch the supply off. Only this morning the pressure reads about 4PSI. Now does this indicate a leak, despite no obvious signs, or is it more likely the lager taking on the co2?.