I have been using a DIY waterfall scrubber for many (10+) years now. (Quite a few of those years using two banks of Turbo's LEDs.) A couple of things though: 1) If I go on vacation, or get lazy, screens do not get cleaned weekly. 2) Algae scrubbers do tend to produce a bit of extra detritus 3) I have considered a rollermat device for normal detritus as well. So I came up with an idea to make an automated rollermat scrubber. The "screen" would be fleece, moving about 1" per day. As water goes through it, it collects detritus. As it goes up in the LED section, it grows algae. As it gets full, it exits top, it dries out, and is rolled up. Monthly or so you replace fleece roll. I already have some worries, but thought I would throw it out there for fun.
Some concerns: 1) Weight A full scrubber screen, with pump running and water falling, is not light. Especially my fairly large 10x12 screen. The roller and motor would have to be really strong. Not impossible, but adds cost, and means metal parts. 2) Seeding screen As you replace the roll, the new screen is clean, and it takes a while to really establish a good hair algae base. Similarly, as it goes up, the bottom is new and clean, and that part will be shaded by existing growth from above, so may not seed well. 3) Not efficient mechanical filtration Ideally you want dirty water to pass through the fleece from one direction. In this case, it is passing down along it. Detritus capture will not be nearly as good. 4) Algae dust As algae rises up, it dries out (deliberately) and is rolled onto roller. But as it goes up and bends, it will crinkle and crush the algae. That will probably cause pieces to fall off, and even get back in the tank. So I am not as excited about the idea.
