ok did a little test last night for flow , i added a small amount of dusty sand then added one powerhead basically pointing straight down.
nothing settles in the tank anywhere, but heres what happens.
the flow pushes straight down, then hits the bottom and goes across the bottom of the tank then shoots straight back up....a giant loop.
if i add a second powerhead to the other side i get chaotic turbulence and sand going everywhere.
im skipping any substrate and im going with the classic return and drain scenario......i think flow is going to be fine with one powerhead, if it doesnt seem to work ill try it out with both....ill have to wait and see what the corals say about it
now to try to find some tiny bulkheads hehehe;P