Update: Blackout worked! For the most part, at least. The tank's resident planarians went nuts during the blackout but are gone now that the filter and light are on full blast. There are still a few patches of the filamentous algae, but they seem to be "in remission". I'm not sure it's hair algae; I think it might be spirogyra instead. But no matter, it's under control.
Apologies for the weird purple tint. My camera is aging. :P
5 RCS will be arriving soon, courtesy of epicfish, and I also have some Süßwassertang on the way.
JennaH - you should try a moss lawn! All you'd need are a few stones to make an Amanoesque grassy field.