Okay, I'm setting up a 15g nano reef but I'm buying stuff bit by bit. So far I have aragonite sand and appropriate reef salt and this Thursday I'm picking up a filter; an Eheim 2215. What media should I use for a reef tank? Will I need additional flow? I'm only planning on keeping soft corals and other types of easy coral as this is my first venture into salt. I'll take any other advice I can get, too!