Feeding issues, circulation issues, filtration issues... all causes of "algae problems" such as you describe. While true that all new tanks will go through phases of algae growth, what you are describing sounds more like a problem instead of natural growth.
I agree with continuing the water changes, but it may also take adjusting the water flow, adding a power head or even just changing the direction of the power head, and also may take adding some filtration.
What type of filtration are you currently using? What animals and how many are in the tank? What is your water temp? water params for ammonia, nitrite, nitrate, pH, and calcium? What kind of substrate is on the bottom of the tank, sand or crushed coral? What foods are you feeding and how much, how often? How much water are you changing during your water changes, and how often are you doing this? Is there a buildup on the water's surface? How often do you empty your skimmer cup?
We'll help all we can, but need answers to these questions first...