Im not really sure, cause even just plain CO2 tanks need to be tested every 4 years or so. So an Air Tank runnin C02, I would assume would need tested still. Its just what I think, I dont really know for sure. Illl try and find out
erk so how come co2 tanks dont have dates on em? i didnt reliase they even needed testing, and if you are running an air tank with co2 in it you have to change the valve so u cant put air in it anymore