I like you am seeing GHA in my tank and trying to nip it in the bud before it gets out of control. At the moment I have reduced feeding, reduced time my T5 lights are on by 2 hrs per day, closed the blinds in my room so no sun light enters (this step alone has already stopped the little amount of diatoms I was still experiencing), doing more frequent water changes, and manually removing what I can. I also added an urchin to help the turbo snails eat it. My next move will be to run an algae reactor for future nutrient export control. There are so many ways to attack algae issues it really depends on what works best for your situation. I try to stay away from chemicals until I feel the breaking point (except with cyano, I just hit it with Red Slime Remover and move on).
Good luck, this can be a long twisty road, but it's fixable if you start making corrective measures immediately!