I would try to put it into low flow at the bottom of the tank. I have several Cyphastreas, and they don't tolerate high flow in my tank.

should it be on the rock or could i place it right on the sandbed?

I have two in the sand, and one is attached to rock. They don't seem to care as long as they don't get too much light. I have halides, and they literally have to be in shady spots.