Purple Bonsai browning out a bit..thoughts?

[ashr]

hey all

Looking for some help. This is one of my fav corals but I have had to change the way it faced in my tank a couple weeks ago. It was turned the opposite way that it is facing now. The back of it, where less light got to was always pretty tan/not super bright. But now that I changed the way it faces it is turning brown on the one side.

Nothing else is really browning out except for a purple arco that I had to frag and it is starting to color up again.

Thoughts?

Calc 440
Alk 8-9
Mag 1450
S/G 1.26
Phos 0.19 (a little high)