If im not mistaken there are different gauges you can use to tell what's left in the tank, I remember seeing some before. I know on mine the red/green gauge isn't super accurate but gives a rough idea without picking em up or other ways listed. Plus mine runs the dual tanks like most and swaps over automatically when one goes empty. I've got good at guesstimating just by picking em up, been living in my trailer several yrs now. Always hate running completely out in winter and needing to fill fast! I have a 100lb in addition to the 30 lbs supplied, makes it nice. If there's room when camping I suggest a spare tank.