Help my case coral seems to be bleaching

[Mightythias]

Had this case coral for a long time. And has been in this tank with the same lighting condition and tank parameters for about a year. Was doing great until about 2-3 weeks ago. The color started to fade dramatically from the vibrant green to a generic dark color and now it is beginning to bleach and turn white from the underside. What is happening? What can I do to reverse or fix this? My parameters are always pretty stable.
78f temp
1.026
pH usually steady around 8.1 but my probe broke so I haven’t monitored it super closely the last few months.
If you look at the first photo to the left of the clown you can see the bleaching.
Then there are some comparison pics from when it looked great back in November and October

 

[Spare time]

Can you list the numbers for calcium, alk, magnesium, nitrate, phosphate, salinity, and what test kit you use for each?