A very, very mature tank.
I can almost comprehend getting tired of a tank that there is really nothing left to do in, except prune corals.
Might either be time for a larger tank, or starting all over with another.
Sad to see someone that has done such a great job developing such a system getting to point where they want to sell it.
Certainly would never get what put into it.
Would make a great display tank for a business or LFS. (or sitting in my other living room.
- just kidding, very happy to watch my own "grow up"