I'm only using a bio-pellets reactor. I had huge hair algae problems for more than 2 years. I am not good at often maintenance, so GFO didn't work for me because it takes rising, monitoring, changing, etc. The bio-pellets is almost set and forget: filled it up with bio--pellets, then every 3-6 months clean its pipes & grills. Oh, mine is hooked up on the main return pump, so I don't have an extra pump to clean.
What worked to get rid of algae for me, was to basically leave the tank alone to consume all the nutrients

. I helped with aggressive skimming, bio-pellets, refugium & pulling out hair algae from rocks. Other than that, I kept the livestock as it was, I didn't add much other than a few snails & crabs to it, I made sure not to overfeed and to use good RO water when doing water changes. In about 3-6 months I suddenly noticed that the algae doesn't grow much on the rocks, then it completely disappeared from main tank, being eaten by fish & CUC.