Cyno outbreak. Please help. Oh and the clownfish has decided to host a patch of it

[Safarali]

Hey guys wanted to say thanks I have been doing 20% water changes every 3 days. I turned the lights off. But the tank in is my living room so it's getting light no matter what. Well less then the led ofcourse. So after 3 days of mid blackout. The cyano has not been growing and kinda turning black (much less in mass as well). Is that weird? Should I continues the no led thing for a while longer? Been 3 days?

[Origami]

Try to siphon out what you can. Loosen it with a brush or blasts from a turkey baster if it's not coming off easily.

 

Because of amibient light, lights out often means taping up (or clamping) brown paper, blankets or something else around the tank to stop light from entering the sides.