That is where I have 3x mp40s lol. Blast the crap out of the macro and it then shoots up the back side of the rocks and keeps all of my acros nice and tidy. The upwards flow hitting the flow up top also makes a nice random "busting" all over the tank. It also flushes an detritus that could settle off the acro bases.My big tank has a pretty gnarly flow pattern through it. All 4 return lines running at the high end of the RFG limits (1800+ GPH), reefwave 25 on the back and 45 on the end running opposite of each other. There is only one place in the tank where water constantly moves in one direction, and that is the rear channel, behind the rocks.