this is what drives me crazy. people always say they have a problem with cyano. i agree, you guys probably do, but there are 2 simple solutions:
1. evaluate your flow. try changing the position of your powerheads, or if you dont have at least 20x turnover of flow, get more PH's.
2. do a water change!!!!! the only way cyano can survive, is with food! the excess nutrients in your tank are feeding it!
hope that helps