What size was you thinking on your ATS. I have seen a few and they take up some room and like most things live take more maintenance than I would like to deal with and they also gave off an odor. I guess if you are doing a fish room and have the time it might not be too bad.
I am getting a 2 cube ATS lighted by LEDs. It is actually not that big and will sit on the fuge chamber of my sump (6x6x9 inches). I saw some of the original ATS and they were quite large. This ATS has LED lights from both directions cutting down on screen size. Again, it is something I am just going to try. I did research the odor issue and in the sticky threads about ATS, most people running them successfully with the correct design do not have an odor issue. I have been emailing some of the resident RC ATS experts; they are quite helpful and knowledgable. Of course, being a DIY idiot, I am going to not DIY this project.