Just in case the RC link gets taken down (which they do from time to time) http://www.reefcentral.com/forums/showpost.php?p=23179436&postcount=6209 http://www.ebay.com/itm/Algae-Scrubber-Tank-mounted-/271628780964 Cheap chinese scrubber. They still are just skirting around the whole concept of the waterfall and UAS, this one is neither, it's a submerged vertical one-sided with what does not look like a roughed-up screen. I had something like this on paper at some point and never ran with it. However, I've had some recent brainstorming (in a different direction) and I've now realized that it might be possible to make my next version flexible enough to use as a standard waterfall or an HOB type. Actually not really HOB, as it would not "hang" on the back of the tank, because a true waterfall scrubber (which I believe is the most efficient type of Algae Scrubber) cannot hang on the back of a tank without draining to a sump.