Take a look at your rock structure and make sure theres no 'dead' spots in the tank. Adding an extra power head and adding more flow can certainly help. Once I re-arranged some rocks in my tank, and added an extra Koralia, it was able to get to the nasty stuff and kick it up, to be sucked up by the skimmer.. which of course helped with the algae / cyano since all of its 'food' was being filtered away.