Caulastrea change in look?

[kilnakorr]

Not sure how to describe it, but my caulastrea has started to look less smooth, and with a different 'structure':

The color difference is most likely light difference /time of day.
The darker rings are more visible the last week than ussual.
Anyone knows why?

 

[vetteguy53081]

Moderate light and water flow and are you feeding?
At the number of heads , I would assume you are. Light dictates color
They’ll be brighter midday versus morning and evening