There's no need to have a reflector for your basking lamp, not in a vivarium anyway - I don't think most people bother. They are mostly used as holders for above glass terrariums.
Where the viv is not very tall and/or the lamp sits too low and you are trying to get some height between the lamp and basking point/s, then they are sometimes used above a hole cut in the viv roof. Provided your temps are right and there is room above the viv, it can be a neat and tidy solution.
Last edited by Spot; 20-02-2013 at 02:16 PM..