I don't think that is the issue.
When I raise KH above 7 all the corals in my tank become very dull whitish. everything. Things color up much better around 6-7 KH.
I am dripping vodka/acetic acid mix into the system.
As many others have noticed in this situation a high (9-11 KH) often does not work well.
This also does not explain the fact that I have multiple other candy canes, montiporas, and hammerhead corals all doing fine. Only this one is having issues.
I don't think its current either because I swapped the positions of the coral doing well and the one doing poor and that has not made a difference.
2 months ago both looked great.
this is a specific effect on a single coral in my system. I do not formally know that the two frags are from the same mother, but I suspect so, since I bought them at the same time from the same store.