I'm new to this propane game so I'm still learning. We took our new 1475 out for 5 days last month, did some cooking and heating of water and air, but ran the fridge on shore power. We are generally frugal with heat, been keeping our house at 61 during the day, 59 at night. The Truma was set pretty low at night. The dealer supposedly gave us a full LP tank. So I have no idea how much we used.
I tried the hot water trick on my tank this afternoon, had absolutely no idea what it was telling me. There was a difference in the wet tank surface above and below the central weld, but I don't know if was real or if it was just the way the water rolled down the surface and past the weld. I could imagine I believe I thought I think I saw a difference between the surface on the sloping curved top surface and the vertical side, but since the slope was changing I have no idea if it was believable.
Bottom line, I have no idea how much profane, I mean propane is left. I'm leaning toward wanting a tool that gives me an unambiguous reading, even if I have to try it three or four times to make it speak. That Dometic pencil probe is looking nice right now. Of course we won't be going out again for several months, but I don't want to get two days into a planned five day trip and run out of propane. Then my speech may actually become profane.