circulation pump help!

A lot of that will depend on your rock scape. Make sure you have flow around and behind all the rocks. I would start with one on each end of the tank. Stagger them front to back, and top to bottom in the water column to try and make a circular flow through the tank. Watch how everything reacts and see if there are any dead spots that accumulate detritus. Sometimes you just won't be able to get flow everywhere and you just have to make sure you keep the detritus cleaned out frequently.

 

If you get 2 streams hitting each other in the middle it creates a lot of turbulence and random flow, but it also creates a lot of dead spots. I'd start with one high and one low, stagger them so one is more towards the front and one is more towards the back. You'll also have to adjust them so they don't kick up sand and aren't directly hitting you corals. The LPS you have won't like strong, direct blasts from the powerheads.
There's no definitive answer that will work with every tank every time. Its trial and error to find out what works best for your tank the way you have set up. The important things to watch are that your corals are happy, and that you have minimum deadspots that accumulate detritus.