I think with that kind of water volume you run into new areas of concern as far as being able to actually circulate all of that water around properly. I have no experience with a "tank" that big but I've learned a lot since I've got into fish keeping. I know in my experience with in ground pools, moving the water in stagnant areas which is not so much a concern for swimming, (why we have polaris cleaners etc) may be a problem for fish. Wouldn't you need to start fabricating custom components to move all that volume uniformly? I'm interested at the replies from people who have tanks this size.