bubble coral help

[4ptbuck]

I have a green bubble coral in my tank that now has some brown colour to it. When I first bought it, it was a 'pure' colour. Now it looks like it has mildew inside it.

It is currently located at the top of my tank, directly under 2X96W ( 10K and 50/50).

Does anybody have any ideas what might be happening? It has slowly developed, and the 'mildew' seems to be spreading.

I got a feeling it might be getting too much light, as the portion that is not directly under the tubes seem to be 'cleaner'.

Here's an earlier pic.... It's worse now.




4pts....