Any pics of successful, slick hang on back designs? Seems hard to find.... and would be great for the standard medium sized tanks. I am not so interested in the sump designs, which dominate. I guess they are easier to improvise, but I had a sump refugium which was problematic to me, given the not-foolproof siphon overflow box, water draining noise, and humming laboring return pump.
I like the CPR Hang on Back refugiums, would be nice to transform into an ATS, using their acrylic box and lighting system, but maybe can't work. Just buying the refugium is so easy....