well, it seemed like an odd idea to me too, but looking at my rotala rotundifolia, this stuff only grows on it exactly where the LED hits it directly. My amazon sword is also directly illuminated by one of the LED's. Most of the stuff that is outside the direct light of the LED's is either barely affected or has no algae at all. I'll take your suggestion and shut off the moonlights for a couple weeks, and I suppose if that doesn't do it then I'll have to fiddle with my dosing.