There's not necessarily a whole lot you can do. Your tank is in its early stages of cycling. So you will most likely go through various stages of algae outbreaks in the first year. Diatoms, green hair algae, possibly cyanobacteria etc. Now if your are heavily feeding or slack on the water changes, then that could add to the algae problem. But you will almost always see some sort of algae throughout the first year regardless. Over the course of the first year roughly, most tanks will find a natural balance and the algae will go away. Then you will start growing purple coralline algae... which typically indicates stable water parameters. This is just my experience. I'm sure others have a totally different series of events in their tanks lol.... this is reefing after all.