Im not trying to agrue against everything you say, john, just trying to get it straight
i don't mean to suggest that you should lower the flow, just saying that you don't necessarrly needs that many powerheads to create the same type of currents
There is a big big difference between having 1 PH and 2 PH's. 1 PH only produces 1 single, boring, circular flow. With 2 PH's, the 2 flows can crash together to create more random flows. If i remember it right, this is what i've read from a book by julian sprung:
There are 3 kinds of water movement in the ocean: surge, turbulence, and some other word that he used for big, one-direction flow. So with just 1 PH, u can't possibly create any surge or turbulence.... Circular flow in a reef aquarium is not suggested.
Also I really doubt that any reef tank can be healthy from just the flow of the returning pump with no pumps/PH's to create additional flow. Filters and returning pump only create a small water movement on the surface so without any additional PH's, there would be dead spots all over the tank.