read read read! thats gonna be your biggest money saver..... as far as what corals will do ok under t5, it depends on the fixture, how many bubls, individual reflectors, etc..... id say expect to fork out about a grand, as far as pumps and skimmer for that tank, just look em up on here, they all have reviews and stuff, ive never done a reef that small..... keep in mind, the more water volume you have the easier it is to keep it stable.....