Fill 20# tank from 500 gallon tank?????

[gasman1075]

There was a class action lawsuit a few years ago because some of the exchange companies marketed them as " 20 LB" when they only put 16-18lbs in them. small DOT Cylinders should be filled by weight on a scale. Tanks ( ASME ) are filled by volume. Larger DOT cylinders are also filled by volume when at customer locations......if I am running a space heater I also have a CO detector in the same space.