That's great thanks, just a couple more questions on this. How can you tell the difference between a land only tank and a diving tank? And what is the test intervals if I were to buy the diving tank. Any clues where I could fill it too? thanks again
Don't take it as gospel - but scuba cylinders need a visual test at the 2 1/2 year point (including internal viewing), dependant on the condition it either passes or may be shot blasted for any corrosion and then be subject to a full hydro test.
On the 5 year point they are subject to a full hydro test.
A surface use cylinder won't need the interim visual inspection, however it may be up to the dive centre that you turn up to if they accept the last test date. (It may be as simple as a 'surface use only' label)
Specifics on test regimes may also vary for the cylinder classification.
It would be best to speak at your nearest dive centre and get the specifics from them, and dive centres would be the main source for fills