It's hair algae, but it's possible there could be bits of dinos mixed in. A close look wouldn't hurt. Do you see any brown stuff in there?
Do you know if your hermits are dying off?
If I were you, I might try upping nutrients a little, until both are detectable and not hovering near zero. Your rock isn't too white, and I do see some coraline on there. It's worth a try to get that other algae growing. Especially if you don't have any corals to worry about the algae overrunning.
Did your tank ever go through an ugly stage? A big surge of rampant pest algae, that gradually faded out?
Do you know if your hermits are dying off?
If I were you, I might try upping nutrients a little, until both are detectable and not hovering near zero. Your rock isn't too white, and I do see some coraline on there. It's worth a try to get that other algae growing. Especially if you don't have any corals to worry about the algae overrunning.
Did your tank ever go through an ugly stage? A big surge of rampant pest algae, that gradually faded out?