I have a 12-13" arowana living in a 75 gallon. Obviously getting small, so I'm going to build a pond. My current thought is to make a pond out of plywood with 2x4 and 4x4 braces, (steel braces on the sides of course) with a 45mL epdm pond liner. The dimensions would be 8x3x3. Can anyone who has done this tell me if it works good? I'm worried about the wood bending eventually, just not sure. Any advice is welcome.