All you need for proper filtration for a nano is a protein skimmer, live rock (1lb./gal.), and live sand (1.5lb./gal.). You will have 4 watts/gal. if you run 2-24 watt PC's . That is good enough to keep mushrooms and zoas, but you might want to ry to jump up to 6 watts/gal. if you want any SPS.