3day blackout

So I have a display refugium I’ve made a few posts about and I’m battling some cyano in it. I’m thinking about doing a blackout for 72hrs to try to kill the cyano. Will my macro survive that? Or will I just kill it all?

My 16 gallon reef has been stable for the longest time, until I got bubble algae and started to increased my water changes which got to a point where my nutrients were too low and now I have dinos. I had dinos about three weeks before I decided to do a blackout and all of my coral was fine, but...

I’m looking into doing a 3 day black out to try and help with hair algae. I have corals and 1 anemone in the tank. Does blackout mean all lights off for 3 days or just on a low setting?