I like the idea(and the illustration), and think that having the water flow over halfed cork bark could add some tannins to the water. To be honest, if you are going to have a water resevoir at one side as shown above, I would use a false bottom. It just keeps the water better filtered and circulating. Good luck, and that is a MONSTER tank! I am jealous, where did you get it?
JBear
JBear