First off, just gotta say, I loved the dig that Reefbuilders did against Santa Monica today in this article: http://reefbuilders.com/2013/11/20/draftrevisiting-refugium-accurately-macroalgae-scrubber/ After so many years of playing around with the ATS concept and seeing others experiment as well, to me, it seems there isn't a whole lot of difference between methods in terms of filtering ability. Provide location to grow, adequate light and flow, and your done. My 75G tank used to be run off a 15G sump and did fantastic. Since experimenting with ATS's I upgraded my sump to a 55G, unfortunately a 48" sump doesn't fit under the stand of a 30" wide tank. It was fine having the large sump outside of the stand for experimenting purposes, but to me I think I have come to my 'conclusion' in regards to utilizing algae as a filter. The idea, this is still in my head as I am in the process of removing old baffles out of my 15G sump and re-siliconing them back in a different way to fit my idea... but the idea is simple. No waterfall, no box above the sump, no airpumps, powerheads, floating foam... simply plastic screen and a couple little strips of acrylic. For now your going to have to picture this in your head until I get it done and take some pictures. 15G sump, 24"x10"x12". Chamber 1: Overflow into filter sock (after years of not using them, with a decade of using them before I quit, I am now going back to using them) Chamber 2: The magic - Previously I had this filled with caulerpa, and it worked fantastic, which told me I had plenty of flow to feed algae and filter the tank. This time, I am going to silicone a few little strips of acrylic to the sides and bottom of the second chamber, 3 sets of 'slots', these will be used as guides for the screens to slide into and hold in place. Then simply place 3 cut to size/roughed up pieces of screen into that chamber. Yes, lighting isn't going to be 'ideal' having the screens vertical and having LED lights above the chamber, but I feel we have gone way past the point of 'being able to give too much light', so I don't feel lighting intensity will be a concern for algae growth with lights above. Basically, I am just giving much more surface area in my 'refugium' section and switching algae species from the last time I ran the 15G sump. Chamber 3: return pump My tank is bare right now, going though an ich outbreak/copper treatment, so only sand is in the tank (for the wrasses to sleep in) and that will be replaced once treatment is over. Rocks and corals are in a holding tank for now, but my goal is to have my tank/sump redone and back to a reef by the new year. Any thoughts on my 'SSAS' (Super Simple Algae Scrubber) idea? Another idea for sumps already in use is to figure out a way to fasten magnets to the screen and have 2 magnets on each side to hold the screen against the walls of the sump. The only thing I can think of is flow.. as the above article points out, flow in the algae section helps a lot. For me, I accomplish this by having a 1200GPH return pump on a 15G tank, that really pushes the water through the sump and goes against most advice (water flow should be slow through sump to allow adequate time for filtering, but now I really think that is a falsehood as stronger flow actually provides better filtering due to less settling of detritus that would foul up and lower algae filtering ability).