actually its not tough, the idea is a very low cabinet and shallow tank with a glass or acrylic lid, no lightings and the only corals you can keep are sponges and sun corals, the sump will be hidden in the cabinet.
a friend of mine used to have 1 and all he kept inside is a blue ribbon eel that slides all over the place , no big rocks , just a few small pieces here and there to give a beach sandbed look