SPS tissue receding

Help please:

I don't know what this SPS is called but it is my favorite in the tank. As you can see on the edges the tissue has began to recede. It just started 2 days ago and appears to be worse today. this has grown 3 times its size in 6 months and all of the polyps are still fully extended. Nothing has changed.

Params:

KH: 8
Mg: 1400
Ca: 450
pH: 8.0
SG: 1.026

They stay quite stable. Should I cut the dying ends off and treat with an iodine dip, just dip, or do nothing? I need help please because I do not want this to kill the entire coral. Also every other SPS is doing fine and I have 4 more in the same area.

 

looks like a M. Setosa, from what i know its a lower light sps.

 

Well it hasn't moved it's position in 6 months and was growing at an incredible rate. I don't think lights are a factor. Do you know if the recession will stop on its own or if I should intervene?

 

Personally, I would cut off the receding/ dead parts and dip the entire coral in an iodine bath like TM Pro Coral Cure. I prefer to be proactive when I see tissue recession.