Algae'd and confused

[MikeInToronto]

Which ever way you choose, you want to limit the nutrient level in the tank. This will mean constantly cleaning the rock and removing as much algae and organic material as possible.

If it were me, I'd go dark. I'd put the rock in a bin, keep the lights off, and change the water regularly. I'd scrub the rock and repeat. I may even do this for a couple of months depending on how bad it is. A little hair algae is no big deal; I have a 1 cm square sitting in my tank that doesn't grow (but my tank is also very nutrient-poor).