Im going to be stacking rock pretty high in my tank. When i place the rock in my take should i live room by the intake and return? or will it still function fine with rock right by it?
Leave a gap for unobstructed circulation. Also leave space between the rock and the glass. Position the rock in the tank before the sand so that the rock will have a more stable platform (avoiding rockslides).
I too went pretty high with the rock in my 110 gallon (around 29" tall ?). I left room for the water to circulate behind the rock and into the openings in the overflow. I don't have any powerheads yet but I'm thinking of using 3 Tunze, one pointed down behind the rocks, one on top left and one on top right. From what I hear you want to make sure you have good water flow all around the rock regardless of the height.
I wouldnt point any PH's down...this will ened up causing a sand storm(assuming you have sand), and I wouldnt build any rock structure to close to any pumps PHs, or overflows...you really dont want coral growing on these things, or worse, one of you animals getting stuck, injured, or killed
you want the return and the overflow to be free of obstruction because you will get the best flow that way, the better flow you have the happier the fish will be, fish are used to the ocean which has an immense amount of flow so they can swim through the currents. Fish enjoy flow and so do the corals. If you restrict the flow in any way in the tank you will start to get residue buildup on the rocks and on the corals and also the fish and coral wont be as happy as they could be.