That is a beautiful set up, I love the way you have everything so neat looking in there, not to harp but I would change out the sand, get some nice black tile, that would give the same look and be quite cheap, not need to be replaced and no worries about a sand accident.
i really want to get one of those magnetic caves that has the part that attaches on the outside of the tank to make it dark inside once i get my setup, what size is the one in yours?