I'm wanting to build a small indoor pond in the entryway of our home. Nothing bigger than about 4 ft by 2 ft wide; maybe with a small waterfall cascading down some rocks. It will probably be fairly shallow - maybe about 1 foot deep. Our home is older so I am concerned about the weight load of several gallons of water - not to mention the rocks that I'd like to surround the pond with. What are some considerations/concerns I should be thinking about for something like this?