I recently installed that model and I have a 4" - 5" sand bed. I shoots across the tank from the left side to right slighly angled to the back so it hits the rock. I have it set 3" below the surface of the water. It moved a lot of sand out of the way. But, once it settled in its new location, I distributed elsewhere and the rest of the sand had not moved. It moved an are about 3" Long, running the width of the tank. Of course I have a live rock wall that starts there. I think it may not affect a 1" bed. I still have about that much on the right hand side. I put some rubble over the sand in that area to make sure it does not move anymore.
Great pump by the way. My Remora seems to be collecting more skimmate now.
Oh, get the magnet holder. The mounting kit takes alot of rigging. Especially if your canopy sits on the tank.