unwanted algae

I have this light pink, hairy algae growing over my live rock, but only on the rock in the shade. I've been looking all over for what this might be, but cannot find any similar photos/threads/posts about this type of algae(if that's what it is). I recently added some more liverock before I left...

Hey guys I seem to get this algae growing on just the plastic bits of the tank, it doesn’t grow any we’re else. Could it be GHA? My sand bed and rock work have nothing, on the other hand my frag rack and over flow are plastic and are gradually becoming covered. It almost seems as though when...