second picture looks like some bubble algae..Its something you dont want to have in your tank. Its a headache and will spread, you wanna get rid of that. You can take that rock out of your tank and scrub them off with a tooth brush. Be sure to have a bucket of clean salt water to rise it off b4 you stick it back in your main tank.
since your tank is new thats the only way I can think of to get rid of it. possible an emerald crab can help, but if you see any you should try and manually remove it before it spreads.