Cyano is bacteria and not algae. Cyano is usually due to over feeding as the uneaten food lays on the bottom and the bacteria is able to pull nitrogen and or carbon right from the decaying food even in a black out. Cyano needs to be in a total black out to get rid of it if its really bad, by total black out I mean the whole tank needs to be covered and the room, it needs to be black as possible as well. Cyano lives with out much light because its photosynthetic, meaning it can remove the food it needs right from decaying matter without the need of light. Even if in a very dim situation cyano can live a very long time, even in a pure black out it can live for up to a week-ish. The best thing to do is to cut your feeding in half and reduce your lighting in the display and see what this does. You might even have to get some stronger light for your scrubber if its brown algae you have growing. I know what you are going through!! I went through the cyano as well.