It seems I may have a tank leak. Now that my wings are complete I figured Id pressure test the tanks again with all of the fittings/sight tubes installed. I first tested them connected together at the main fuel supply ports and plugged the air vent line (with a plugged tycoon tube) and fuel caps (with sealing tape). I blew into the tanks enough to get the tape to bubble. I found this configuration leaked enough that the tape wasn't bubbled after about 12 hours. Then I separated the tanks to test individually. They both hold lung pressure for about 24 hrs before I can no longer see the tape is bubbled. So both tanks seems to leak at about the same rate and quite slow.

Im wondering if I should be concerned or if this is what others have observed. Im wondering if the quick drain might leak air but not fuel. Or if the tanks should hold air indefinitely and I need to go searching for leaks at each of the fittings.

Thanks for the help!