I am mid-cycle on my tank right now, i use Liverock as my natural filter, and also have a BakPak II skimmer. You are gonna want two powerheads, maxijet 1200's should be good, probably two heaters. 3-4 fishes? are you talking to cycle your tank? a lot of people would recommend using two raw shrimp instead of damsels. It has the same effect and you are not torturing fish and you dont have to worry about taking them out after your cycle. Good luck.
50 Gallon Oceanic: 2 maxijet 1200's, 2 150 watt visitherm heaters, BakPak II Skimmer with PS & BT, Coralife Lunar 2X65 watt Power Compacts
Filtration: 50lbs LR
.com, 60lbs sand
Swimmers: 2 O. Clowns, Yellow Watchman, Firefish, Yellow Tang, Dottyback.
Clean-Up: Several snail & hermits, Skunk Cleaner, 2 Peps.
Corals: 2 zoo colonies, yellow polyps, star polyps