I just turned one of my freshwater ten gallons into a FOWLR setup. There are 4 lbs of LR in the tank, a powerhead attached to a sponge filter, a blue damsel, blue legged hermit crab, and 1/2" of arganite sand. The light is a 96 watt 6700 deg K CF light. I am planning on using the Berlin method as a means of filtration. What should I get next, a protein skimmer (if so which one) or more live rock (if so which one)?