You should be able to swap it. A vertical 20 is a vertical 20 as far as I know. However, I don't exchange unless I absolutely have too; I get mine refilled. If you read the fine print an exchange tank from a hardware store is not full. A full tank contains 4.7 gallons. The exchange tank is usually around 3.7 gallons. Also, it's more expensive by the gallon. I've gotten my empty tanks filled with 4.7 gallons for around $17 to $19 depending on when and where. What's an exchange cost for a gallon less?