Why dont you look at getting the Arcadia slimline set up? It comes with everything you need including tube and reflector, save you having to buy everything seperately and costs pretty much the same as it would if you brought your starter, tube and reflector seperately. Its all made to fit together so the tube is built into the reflector and it only has 1 wire going into it. It looks better and a lot neater than having 2 wires going into your viv.. Again this is the T5 12% tube, like others have said.. wouldnt recommend any other UV tube if not only because it lasts twice as long as any other on the market.
Arcadia Slimline Vivarium Canopy and T5 Lamp
For a 4ft viv you would be looking at the 39w tube (3ft)