Purple SPS Turning Green?

I'm not sure what the deal is. I keep my alk around 9-10 dkh. You might want to raise it a bit. Also, it appears to be in a different location than the first pic. Maybe you should move it back to where it was doing good.

Thats exactly what i did and in the process bit bit about 25 times by my damn maroon clown, fiesty lil bugger he is, glad he dont have teeth.
Like i said water parm's seem to be jus fine, Calcium is at 450ppm...I moved the monti back to a higher flow area, gunna give it a couple days and see what happens, if i dont think its hoing to pull threw ill jus take it to theLFS and he can have it. It takes up alot of space and i got it for free from a friend when i first started my tank. I dont think i have those hitchhikers Brock, at least i hope not lol.
Double check the monti to be sure. Those are some nasty lil buggers! Hopefully you dont have them, I apologize I can be paranoid at times didnt mean to spook ya
Im going to keep a close eye on it today...do those come out at night or just feast when the lights are on.....and no bro, its good you even mentioned it because i never knew about those.
Im pretty sure they come out at night but during the day they would most likely be on the underside of the monti. Just flip it over for a quick look