AmericalVette: Easiest way to "estimate" propane level is to use a bathroom scale. Assuming the tank will sit on the scale, check the TW "tare weight" engraved on the collar of the tank. A 20lb tank will usually weigh in the neighborhood of 16-18 lbs empty. Full, with 20lbs of propane it would weigh 36-38lbs. (adding 20lbs to the TW). So if you have a 20lb tank that weighs 26 lbs with a TW of 16lbs, it has 10lbs of propane in it. Same applies to 30 and 40 lb tanks...just subtract the TW from the actual weight to get the propane weight.
