so I am playing with the idea of making a pond that is semi underground with a window in the side. has anyone had any experience with this. I have found a few places that make stainless frames for this reason but man they are expensive and the only ones I have found are from overseas so add a butt ton of shipping on top of that. I would like to make the above ground portion out of timber and line it with a regular pond liner. what is everyones thoughts?