I have about a six month old sulcata tortoise. I went to check on him today and notice his shell was was black. I am really concerned about him. He is moving, eating, and not showing any symptoms. He is behaving normal for him. I gave him a bath and moved him from his outside enclosure. He has been fine out there since I built it a couple months ago. I move him in and out often. The outside enclosure has filtered water and is in the sun with hides. Ignore the clacium powder on his face.