When my lighting system blew out and I had no lights for over a week, I noticed that after I got my lights back up, the hair algae that I had (didn't have too much because I kept it under control with pruning, etc) wasn't growing as much. Pruned it again, and it's not really growing back. And to let you know, I have SPS and yes, they didn't have lights for over a week...wasn't a big deal for them. Might try this method.