Mine 29gal is the standard model(30X18X13) and I have a 4-5" sandbed with 35lbs LR. Well depending on what corals your are wanting, current is one of the most important things. If you wanna have a rough estimate of the turn over rate of your water..ie.. current flow, then plan to have the total gallons in your tank to turn over 10-20 times. That would need a total of 300-600gph. I'm running mine to where the water turns over 13X an hour when the skimmer is running and when it is not it's about 20X an hour.
I use Maxijet PH's,on the right side I point a MP 900(230gph) at the surface, place one beside it, MP 600(160gph) and point it towards the front of the tank, and on my skimmer I have a MP1200(295gph) and it flows downward towards the left front of the tank.
Current is an nessesity with corals, also it helps prevent algea outbreaks.
Good luck