You just have unstable water conditions, typical of a new tank. I suggest two things: Keep the water conditions stable by removing and replacing a minimum of half the tank water every 6 to 7 days. Just replace it with pure, treated tap water. Large, weekly water changes are the best way to keep water conditions stable and will remove the extra phosphates and nitrates algae needs for growth.
Also, during the water change when the water level is low, plant a couple of hardy stem plants like Water wisteria and Pennywort. These will use up any left over nutrients not removed by the water changes.
By removing the bulk of the food in the water, the algae will strink to a more manageable size. A little is a good thing.
"Fear not my child, just change the tank water."