Experience with UV sterilizers

Hi everyone! I have a 120gal. Freshwater tank that I have been un-successfully battling black beard algae in. The tank also has tiny little scratches in the inside glass from a previous owner scrubbing it (I didn’t know this until I set it up) and green algae grows in the tiny cracks and it is really difficult to scrub off. I’ve been removing decor, soaking in bleach, scrubbing, etc but I’m considering adding a UV sterilizer. Will this help with the black beard algae and not just the green stuff? Thanks! Product recommendations are also welcome.