Depend on what type of tank you wish to have, it seems you have a FOWLR right now, which means you can upgrade to reef with the right equipment. Also, look up adding perhaps a sump or fuge or both in the DIY forums, this will give you tons to work on. Tank looks good btw, however, if you plan on going reef I would recommend getting rid of the damsels, they can be extremely aggressive and will be hard to catch with alot of rockwork in lace.