The pumps are currently mounted to the sides of the tank stand with a piece of rubber between them and the wood. I also used rubber washers on the screw heads to reduce any more contact. I have found the source of mose of my humming noise, it is the pump mounted on the back panel of the stand. This panel is not solid there is a large hole where my plumbing exits so I am assumimg that this has weaked the ridgity of the panel(3/4" plywood) and allowing it to vibrate. I guess I need to mount the pump differently.
I noticed that if the plumbing of the return line touches the stand it vibrates alot, whatever you do just don't make your plumbing touch your stand...