I bought the Drs. Foster and Smith Semi-Automatic CO2 setup a little while ago and was wondering where to get the proper CO2 tank from. I saw on the instructions of the Azoo regulator that showed a nice CO2 Depot but I can't find it anywhere to buy. All I have seen are the upright standing tanks that have the hole coming from the top, not the side. I was wondering if there's any danger in having a 20oz CO2 tank on its side. I thought it might be dangerous and harder to place in a steady place than the Azoo one. I'd appreciate any help.