I just got a 20lb filled by local guy. talking with him he watch for use the exchange places. (gas stations, blue rino) thay only fill the tanks to 15lb-17lb. you are still paying for 20lb. look at the plastic rap on the tank it tell what thay fill them to.
Gotta have room for thermal expansion.
so when its stamped into the tank 20lb tank means that its 15-17lb tank?
The tare weight (what it weighs empty) on a 20 lb tank is usually 17 lbs, so when it is filled. it shoould weigh 37 lbs. All the tanks have to have the tare weight stamped on them. The tanks you "buy" at the corner store are usually loaded "light". How are you gonna check it when you purchase it? The only sure way you can make sure you get a full tank,is to take it to a place where they fill your tank.