A skimmer would make a lot of difference. When the Venturi on mine clogged, the nitrate went up, and I started seeing cyano. It all got better when the skimmer was running again.
You might also think about a refugium. CPR makes a nice HOB model, if you have room for it. Put some playsand, critters and chaetomorpha algae and it will help sop up excess nutrients.
As Brian said, patience is also a component. The tank is still settling down, and the cyano will probably decrease as the tank matures.