For lighting, I believe that seahorses prefer to have a tank that is lit, but not super bright (like the light that metal halide lamps output).
Live sand is not a necessity.
You can use live sand or dry sand. Some people even have success using pool filter sand in their tanks from hardware stores.
If you have any further questions please don't hesitate to ask.
EDIT: This cycling article may be helpful.
The (almost) Complete Guide and FAQ to Fishless Cycling