Millepora questions

I have 2 green milleporas in my tank that have undergone some odd changes in this last week. On one side of the frag they are turning a purple color and have no polyps out. The other side is the normal color. The side that is changing to the purple color are not being directly hit by light and are somewhat close to my mp10.

Parameters are as follows.

Nitrates: 10ppm
Phosphates <.03ppm
Calcium: 450 ppm
Alk : 10-Dkh
Mg: 1400 ppm

 

Questions?

 

Why the color change?

 

Simply shading is what I am thinking. This happens to some of my sps.

 

Okay, its just weird because they hadnt shown any signs of this until this week. Ands its kind of odd because only those two pieces were effected as far as I could tell.

I would maybe even describe the color as a brown, but my blue lights make it look purple.

 

I'd agree it is probably shading. Getting blasted by an MP10 might have something to do with it, but could be coincidence.

 

I went ahead and changed the mode on the mp10 to lagoonal rather than reefcrest before I left for work. It seems lagoonal spends much less time at full speed than reef crest so maybe that will help out if thats any of the issue.

 

One of my acros is bright green on the back and brown with green tips on the front. It's leaning forward, so the green side is exposed to the light.

 

Basically exactly what I have going on here, I only really noticed today because my urchin knocked the frag around and I saw the side facing away from the light.

I figure it'd be more noticable with green sps becuase the color it turned to was so different that the green, it probably be harder to notice on a red, blue, purple, etc....

 

Mine look exactly like that and have for long while now. And its more of a light brown color. If ya frag it, and the brown part gets more light, it'll green back up. I think its just cause they're so thick, it shades alot of them too much.