I have had two cyano
outbreaks in my tanks, and there are five ways to reduce them.
1) Remove any that you can manually
2) Decrease the length of time your light is on
3) Decrease feeding amount or frequency
4) Increase water changing frequency
5) Increase current on cyano
My advice would be to try 2-5 one at a time, to find out what is causing the cyano
On the other hand, if the algea is more purple and encrusting versus red and slimy, than it is coraline algea and you are a lucky aquarist.
As a sidenote, cyano
is not algea, but a bacteria.