Bleaching/paling in middle of frag...

[Velcro]

So I've had this frag probably around a month. All my other SPS (even stuff that I got the same day from different vendor) look great for the most part. This started a few days ago.

Parameters are all pretty standard:
Temp: 78-79
pH: 8.3-8.5
Salinity: 1.026
Alk: 7.0 (rock solid)
Calcium: 420
Mag: 1400
Nitrate: 2ppm
Phos: 0.01 (I do not run GFO)

This piece has been at around 200 par in the same place via T5 w/ royal blue supplemental LED

I examined it as closely as possible and cannot for the life of me find AEFW or red bugs.

 

[Velcro]

Here's a high contrast version to really show the pattern of bleaching.