I agree but it didn’t help i invited it in ya know hahaGreen hair algae is unavailable. I mean it, the idea that you did something wrong triggers me. Bad information is everywhere. The thing at fault is the idea that you can prevent it. It's something that needs to be managed.
If you want to do a refugium for fun and learning, you should. However I seriously doubt it solves the green algae problem.
Try an urchin and a Conch (more snails as others have suggested) if you want to manage it.
As someone who's had refugiums, I'd recommend spending money on coral. My logic is simple - Grow an awesome underwater garden IN your display v.s. growing green weeds not in the display.