That looks like a brand new tank full of very bare rock.
How old is the atnk and can you post your most recent set of test results?
How long has livestock been in there and what and when did you add it?
Please look forward to your rock losing the dead grey color as it becomes covered over in living things.
Expect greens, reds, purples, and lots of different textures including bumpy, slimy and hairy things. Try hard not to worry too much – this is all good, and most common algae are easy to deal with. Never panic.
Avoid spiking your tank's nutrients with livestock or feeding changes. Make all changes that affect the tank SLOWLY. Keep all changes spread out so no more than one a month happens.
Also avoid overuse of any added methods of nutrient removal. Fast growing corals (and algae if need be) are the correct ways to utilize nutrients you put in the tank!