How to tell if an acro is happy or not

water quality/lighting is most important with sps.

high P04's will make em look not so colorful. not sayin thats what your problem is but if you dont keep tabs on things like phosphates you will be miserable with sps.

and rememeber to keep your 3 legged stool balanced (Ca, Mg, Alk)

Some sps require more flow than others. But generally they all like high flow.

 

It can be growth, but too much is usually bleaching. Especially if the tissue starts receding.

 

So I just did a quick search through liveaquaria and mine kind of looks like the color tip acropora they have, Acropora Coral, Color Tip. The tip of each little bud or whatever you call them are purple but the main body is a different color, light tan to brown in some areas.

 

I keep good tabs on my levels. PO4's are very low to zero and everything else checks out great.