Yes all compressed co2 tanks need testing. every 5 years. most of the places that do refills will do test if not I'm sure they can tell you where.
Hmmm.... I just looked closely at the tank and don't see anything that resembles a date. Lots of numbers and letters, yes, but not an obvious date. I'll just ask the guy when I get it filled if he can "interpret" all the numbers for me and tell me what he recommends for hobby usage and testing frequency (if needed).The last date it was hydro'd is stamped on the tank itself. The numbers at the top of the tank are the date.
LOL! No it wan't obvious! I just returned from getting my cylinder refilled and I asked the guy to find the date for me. Even after he pointed it out for me, I had trouble locating which set of numbers again! But now I know I've got 2 years to go yet before needing a test. Thanks for the link!