Turn off both tanks..at the tank. Have the unit checked by the propane dealer...they usually do that for free. A spray bottle of soap water will show you a leak by bubbling at the leak point. Just spray at the connection points...then along the lines if nothing shows up. (you have to have those tank valves open for this leak check.)
"If it can't be reduced, reused, repaired, rebuilt, refurbished, refinished, resold, recycled or composted
then it should be restricted, redesigned or removed from production."