Originally Posted by fumanchu88
so is it bad?
Cyano will certainly spread, and if it's on hair algea it's a 2-in-1 problem. Whatever caused the hair algea and cyano to show up could cause it to spread pretty quickly. I'd siphon it out with a turkey baster or when you do a water change. Do more frequent water changes and perhaps reduce your lighting cycle. That should stop the spread if you get this stuff out first.