The 3' tall cylinder is 80 CF. The next size up is 125 CF, I think. I borrowed a buddies 125 100 % Argon after using the fluxcore for a short time. I did both 1/4 panels, and several other repairs plus a few little odd & end projects and used about 2/3 of that tank. I went and got an 80 CF off ebay $187 delivered and it came with a 10 year test stamp. I had it filled with C25(75% Argon, 25% Co2). Cost me about $50 to fill it. My welds were better with the C25 than the straight Argon.

80 CF Welding Cylinder