Ok guys, since I am relatively new here it is good form to introduce myself.... Hi, I'm Stan (now that's been done onto to more interesting things). I have been reefing for almost 15 years or so and running fuge with macro most of the time. I spent lots of time thinking about the biological, chemical, and mechanical filtration issues of reef systems. The idea of ATS's didn't seem doable for me at the time that I put up my first reef (nor my second). But the time is coming when I will put up a new 105 rimless, if it ever gets safely. The first one was damaged in transit by a skilled forklift operator ;-) I am intrigued by the ATS now that LEDs are viable (still old school for DT). So I have been reading, thinking, and reading more. And now for my plans and please feel free to comment! Build an ATS! I understand the shortcomings of macro (caulerpa, cheto, etc). It seems to me that ATSs are more 'space efficient.' I have a CNC router and some acrylic skills so fabrication is not a big issue. I've built most every sump I used. What I envision is roughly a 48 sq. in, double sided screen (maybe 8" wide by 6" tall plus screen inside). Currently thinking of using a 8" heat sink with fins vertically to give me the 48 sq in light using 4 (maybe 6) 660nm deep red leds (probably steves leds) with 1-2 Royal blue on each side. The ATS will be plumbed with dedicated pump (probably mag 3 or 7 depending on flow). I'm doing this screen size primarily because I have "old" rock (most of it has been in my possession for 10-15 years) and have had GHA outbreaks in the past. With my current livestock, I feed 2 cubes/day (in separate tanks) and will move all livestock to the 105, so I do not anticipate a reduction in nutrient load in the future. I will run the red leds at 700ma and the blues at 700ma on separate drivers to dim blues. What have I not considered? What should I rethink?