It depends. If it's fully cured LR you're using from an established tank, your cycle may be very minor to nonexistent. Sand or no sand is up to your preference. I like sand for the look but there are also pluses to bare bottom, as sand can sometimes trap detritus etc. A rather small tang would be ok for a while in there, but just understand most tangs usually like tanks bigger than that, on the order of at least 120 gal or preferably larger.
