Attention all SPS Nerds!

I have a question regarding my ORA Red Planet Acropora. I recently bought one from the last fall GIRS fest and it was a beautiful green/pink color with great polyp extension. It was doing great for several weeks and then I had to go back to college for a month...When I came back, it had lost most of its pink/green color and turned purple  it also had significantly less polyp extension. I talked to my parents and they insisted it was fine and that they didn't notice the color loss. When I talked to guys at my LFS that said that the color loss could be due to the low alkalinity in my tank and also possibly due to excess nutrients in the water. I have already done several small water changes and added the properly supplements to return the water parameters back to normal.
Any thoughts or ideas on how I can get the color to return to normal? 
Thanks,   Evan

 

I am using T-5 HO, 4 bulbs at 54 watts each. I dont think that the color change was due to the lights because the coral seemed less healthy. I heard that if you put the red planet up higher in the tank closer to the light that it will lose some of the greenish color and have the pink start to darken to more of a red color.

 

iaJim:
How much are the frags of the red planet? and where are you located?

einsteins:
What I meant by "back to normal parameters" was when I got home from school my alk was at 5, I had some nitratres, and my pH was low. My parents got busy with work. I just had my water results tested today and everything was back to normal. green color is slowly starting to come back now.