Acropora changing colors

[LoneStar45]

About two weeks ago, I purchased a white acropora with rose colored tips. SInce Ive had him, one tip is turning a brownish color and several tips towards its bottom are now green. Since I bought him, I havent seen any small polyps unlike my green acro that extyends his all day long. Is this coral dying, did I buy him almost dead, or he could be growing for all I know. Any ideas?
Thanks.

 

[Travis L. Stevens]

There are no healthy white Acropora's. It's most likely changing color because it is gaining its zooxanthallae algae back. Also, it could be turning brown if there are any detectable nitrates and/or phosphates.

Also, it sounds like the coral was very unhealthy to begin with and you might be seeing bacterial or film algae growth growing on the skeleton

Do you have a picture?

 

[LoneStar45]

Here is a photo.