Just wondering if what I'm thinking is correct or if I'm over reacting.

My Green Star Polyp coral is attached to a piece of rock about the size of a softball. It started to get some green algae growing on it in spots. I moved the rock lower in my tank (it was 6 inches from the surface, now it's 10 inches from the surface) and the GSP are really loving it.
Should I remove the algae growth on this rock or leave it be? My Turbo's due graze over this rock but are not putting a dent in the algae, same as my blue legged hermits. The rock looks neat with both the green star polyps and the algae but I'm afraid the algae may continue to spread over the coral.
Will the coral hold it's own ground or will the algae take over? I don't know the type of algae this is but in a few words it's, dark green, dense, about 1/2" long and grows in patches where the coral is not.
My thinking is to remove the rock and pick off the algae.