1st question was why an ATS? Once I figured out the benefits to an ATS I had to have one. It took a lot of research, homework, and talking to knowledgeable folks such as laffingcrow to figure out what system was right for me (Thank you Brian, you helped me out tremendously).
I ended up going with an AQUA Clear 70 conversion to an ATS. It has been on my FRAG tank for 2 months now and working like a champ. Works so good my skimmer was not getting anything. So I took the skimmer off.
Why did I go with an ATS? Several reasons, it is on my FRAG tank and I overfeed mainly because I want to get good growth. It was causing my tank to have a lot of hair algae. My water quality was not as good as it should be forcing me to do 2 water changes a week (I still do just because but I could push it out to 2 weeks or more with no problem).
Here are some sources that I did some research on when I was looking for the system for me:
http://www.algaescrubber.net/forums/...c.php?f=9&t=68
http://www.algalturfscrubber.com/
Just do a google search for algae turf scrubber and thousands of sites pop. There are some threads on sdreefs. Just search for turf scrubber.