As AJ_77 states"allow it to run its course". It is very common to get Cyano in new tanks. It appears to feed on some unknown nutrient produced by new tanks. Once it has run its course it will disappear. If you can't stand the look you could get Chemiclean. That worked well for me and others. Contrary to common belief it is not caused bt Phosphates, and a skimmer will not help.
