I use a pair of Tunze Stream pumps in my 125 gal reef. They have no problem creating flow along the length of the 6 foot tank.
I think your plan will work, but the least amount of flow will be at the left end of the tank. That may create an area for dirt to accumulate.
You might consider 4 stream pumps, one in each corner, so the flow can be directed in opposite directions. This second pair could always be added later.