Review on Mougerk Portable Heavy Duty Crane Scale 150kg 300lbs, Digital Hanging Scales with 2 AAA Batteries (Batteries Not Included) by Mary Crawford

A standard 30 lb RV LP tank weighs 25 lbs empty and 55 lbs full. So if you weigh one of your tanks and it weighs 40lbs, you know it's half full! This is the ONLY sure way to know exactly how much LP you have in the tank, as NONE of the LP sensors actually work. Someone used a real LP scale for this purpose with a meter that reads capacity instead of pounds, which is the perfect product as people these days don't like doing simple math calculations in their heads but for some reason have stopped . Here is a photo of it to show how to use it for the purposes described above.