I've got a 100gallon tank at a rental house, full, and I'd like to return it to the propane company. They just ripped me off for 65 bucks to come pick up the one at my house, and I'll be danged if I'm gonna pay that for the one down there. It would take about 4 of the 100lb ( about 24 gallons ) tanks to hold the propane in the 100 gallon tank. I know the tanks have a liquid level and then gas above, but if I inverterted the bigger tank, would liquid propane flow into one of the 100lb bottles without the use of a pump ? I have scales to weight the 100lber's to know when they are full, and I think I can work out the tank fittings.....just need to know if this is do-able....because I'd REALLY like to haul that empty tank back over to the propane company and tell 'em to stick it. thanks !