[piercho]

I think you are on the right track, and I think running a thin film of water over a vertical growing zone will be effective. On my last algae turf filter I also avoided the effort to "flash" the turf by making the screen move/rotate. IMO it's easy to focus just on that mechanical aspect and loose sight of the more fundamental parameters of Adey's turf filter: exclusion of microherbivores, optimal gas exchange, etc. I was able to flash that filter by surging the main tank, which caused the water flow to the filter tank to surge as well.

I also have sketches for a vertical algae filter but have not prototyped one. As far as an algae growth surface I've considered the porous side (backside) of plain fired tile, or fiber-reinforce concrete board (backer board) for applications like the one you show. You could also just use thick acrylic and run coarse sandpaper over the surface to rough it up so that the algae can attach well and not be completely scrapped off when harvesting. I was using a PFO mini-pendant with a 6500K Venture 150W DE (M81) on my last algae filter and liked the small size, intensity, and tight light footprint of that setup.

My concern with your design would be salt spray rapidly clouding the surfaces that the light must penetrate. In my own efforts to make turf algae filters work, the spray (even from bursting microbubbles 6" away) that can rapidly degrade the light source has been the biggest obstacle I've have to overcome.

If you can bring this thing to execution I think a lot of people would be interested in the results. In well-executed applications I think that algae turf filters have a lot to offer for reef tank husbandry.