I am still learning about saltwater, and my Nano. But i can tell you what's working for me, keep in mind mine is a 10g so you might need to double on things like, powerheads, lb's of liverock and substrate.
aquaclear filter hang on back kind, without the carbon in it....just your everyday freshwater filter, it's more to move water than anything, that and trap larger stuff.
single powerhead, a 200 i think? moves the water enough in mine, you might think about getting two of these...not a single 400.
10lbs of crushed coral, you can use whatever substrate you want but coral has high buffering capabilities, a lot of people like sand too. you'd probably need arouns 20lb, depending on the dimensions of your tank.
10lbs of live rock, it's approximately a pound per gallon. But this is your only source of filtration, so more the merrier (within reason)