Just continue doing water changes probably weekly at least until the cyano
goes down. People want coraline and not cyano
is ugly and can even cover corals while coraline is a nice purple color that will harden on your rocks. Cyano
growing also means there is too much nutrients in your tank. Overfeeding, too much light, ect. It is also common in new tanks. I wouldn't recommend using any additives as this will just pollute the tank more and cause more problems.
here is another thread where melosu posted some good articles