Be sure sunlight hasn't moved with the change of seasons: if it hits your tank during the day, you're almost guaranteed an outbreak. Cyano adapts to 'eat' just about anything, but a well-tuned skimmer and a 3 day lights-out monthly will make a pretty rapid improvement in most cases. The one thing we can take away that most varieties need is light. And if yours goes away at night and reappears during the day, it'll respond.