Hello, my brother in law gave me a 60x18 clarity plus acrylic tank. It seems to be in good shape and I'm going to put it on a shelf in my fishroom. That said I just have glass tanks down there and they sit on the plywood shelves. When I did my acrylic tank upstairs it seemed very important to put a good foamboard under it. Do you think this is necesary in this case? The shelf is level and flat and the tank isn't going to be there long term. I hate to have to buy a whole 4x8 sheet and cut it up. Thanks.