I have had good luck with it in the back plus it is less obtrussive and my wife doesnt complain how it looks. Mine pounds the live rock. Yes I have sand as well and yes it did push it around when i first put them in, now it is fine. I think the wae comes from the sucking the water in from the top and blasting it out with the stream, so long as you have a few inches i think you would be ok. Give it a shot first and see what type of wave you get. I get about 1/2-3/4 wave with it blasting the rock right off the overflow.