Never really realized the HD tank is lighter than getting them filled yourself. I guess I never exactly weighed them or for that matter asked.
Does everybody fill them to 20 pounds when you bring them an empty tank? And for that matter are all the swaps, empty for new filled to just 15 pounds??? Something for me to note in the future I guess. Now that you mention it thinking back since I've used HD I maybe have been changing them more.....Damn......