The "homebrew" CO2 tanks have the same connection, just no pin, instead you use the valve on the top to open/close the cylinder. If you have a filling station already, you're probably all set (though I don't know for sure if the one you have will work). Does it have a siphon in the 50# tank? (So that liquid CO2 is transferred) When they say 5# CO2, they mean it, weigh the tank before filling, and weigh it after. You should be able to put 5# of CO2 in it.