[EagleEyes]

You will have to drill the tank for plumbing. Let the water overflow back to the sump where you can have a pump feeding the sump water back to the display. Get a powerful pump so you wont need two. Then, if the pump fails, leave enough space so that the rest of the overflow water in the main tank wont flood the sump and subsequently the floor. Thats what im trying to do. The sump will have to be at a lower elevation than the main tank though.