Blue Acro Problem?

So there is a space space on the side of my blue acro where there is no tissue/polyps. The coral has been this way for a long while. That being said the coral has excellent p/e and continues to grow normally. Here is the weird thing. It seems that the coral is expelling waste or something from this area. Its not algae or cyano building up, but rather its some sort of grey "waste" like material.

Here is a pic of it after I cleaned the area up, but in a day or some it will be full of the matter I described. Any ideas?

 

It sounds as though there is another animal in that spot as what you are describing is not normal activity for an Acropora. I would not worry since the Acropora is doing well.

 

thanks buddy

So I shouldnt clean the area? Just leave it alone?

 

Leave it alone unless it is causing a problem for either creature.