A major schism in the schools of reef tank philosophy is between having a sandbed and not having one. As a partial answer to the aesthetics and reflective light advantages of a sand bed, the "bare bottom" school advocates the use of "starboard", a white material used to make cutting boards which is fitted to the bottom of the tank to simulate a sand bed.
Do a search on sandbeds, phosphate, detritus,
bacterial turgor, nutrient loading to help you decide which route you'd like to go.
Personally, I have tanks set up each way, and there are advantages and disadvantages to each.