I was having lunch with an owner of a LP gas distributor and we started talking about the companies who offer tank exchanges for about $19.00. He shocked me when he said most of these companies only put in about 15lbs of gas in a 20lb tank! I took my tank to him the next day and he filled it up the old fashion way and then weighed it for me. Just a hair under 20lbs. (weight of tank excluded). It was heavier than I was used to carrying around (and he only charged 14.00). I guess it pays to have your tanks refilled instead of just swapping tanks. I'm a newbie here, and this is my first post. Looking forward to learning from all of you.