Help with monte

[Courtney Lovell]

So this little guy has his ups and downs. He started turning grayish a few months ago then we switch to blue lights (included with evo tank) he looked on the mend then yesterday he turned almost white with only a small amount of orange on the edges. All parameters on test are normal and the SG 1.024. Any ideas
?

 

[Jeff Jarry reef]

What's your ALK I do know low ALK can make a difference.