What would you do?

[lastlight]

in my experience you're going to get some hair algae. sometimes a lot depending on how your rock is to begin with.

with time (and this means months sometimes) you can beat it by encouraging a lower nutrient environment. I still have a bit too but it's no reason to scrap the rock.

[Dearth]

Hair algae is one of those nuisance algae that everybody experiences at some point or another in their reefing career there are plenty of critters that will nibble at it but few will outright eat it as part of their primary diet it is definitely not an overnight fix. Just continue weekly 20% water changes and I your feeding your critters I would go down to once a day and just very little at that eventually it will go away it takes patience is all.