The manufacture states that my 2018 Sonoma has two 20# LP tanks. Does that mean gallons? On the tanks themselves it says 8.5. I am unsure what these numbers mean. At any rate it wasn't enough for a 4 ...
8.5? Who knows, probably some mfg ID. More than likely the dealer added a couple of gallons of gas to check systems. Take them to a true propane dealer, have them purged and filled. Commonly called 5 gallon tanks is the norm on trailers. Rarely 7 gallon tanks will be installed. Heck, with our old trailers two tanks would last us all summer.