theres alot of ways to get rid of cyno. reduce feedings, frequent water changes, remove as much as possible manually, water flow, ectra...They all work. If you want to do it quickly there are chemical options like red slime remover. This one kills some good bacteria too but I know of amazing results with it quickly. I do have one suggestion though that I can see by your picture.
Your koralia 4 pumps are almost the same hight across the tank from each other with very slight angel ( direction ) difference. You aren't maximizing the awesome power that you can with them. One should be a little lower blowing across the bottom of the sand. The other should be several inches higher aiming a little upwards, thus creating good water circulation. The way you have it alot of the water flow is crashing into each other creating turbulant water movement instead of a good circulation flow.
Good Luck.