OK, I am going to play devil's advocate here to a point so bare with me and don't shoot the messenger. The way I see it is ATS apart from refugium types are having a hard time getting full acceptance in the hobby. Now you might suggest plenty if people run an ATS but in comparison to other forms of filtration etc, they still have quite a way to go IMO. I am in the UK and when I talk about my ATS many treat my posts with something akin to suspicion and that they are some sort of snake oil. Another point people seem quite happy for pay around £400 for a skimmer but not an ATS stating they are expensive. Others simply don't think an ATS can produce the results better than or equal to what they are already running. I think one of the issues is that no truly big player in the field of aquarium equipment manufacturing has as far as I am aware has so far produced an ATS of their own. No big name has really endorsed them or given them much air time. I am talking the likes of Sprung here or BRS sure they have touched on the subject but nowhere near as much as other forms of filtration. Just what are they afraid of? I have my suspicions. So we have to ask ourselves why is that? I have my own theories on why and it's all to do with commercialism. At his point, I won't expand on that but would like to hear others opinions on the subject.