Dipping will only stress it more. Do four 5 gallon water changes in a row (one a day or every other day). It will take some time but it will recover. Water quality is the problem here... Either too much or too little of some element. Get it back inline and all of your corals will be happier.
I agree with Tom regarding the dip...Dip isn't going to help and would likely make it worse.
From your pictures, it appears the bottom lower light area of the candy cane is less impacted?
Assuming your nutrient levels are low and no other corals are being impacted, my guess is that the candy cane liked your dirtier water better (since you recently added the skimmer). The water is clearer and the lighting levels are now brighter. Also, if you recently changed your bulbs that would also be a factor.
Ok. I'm making up some new water now. I'll change 5g every other day for the next 10 days, sound good?
I just tested my CA & ALK using new kits and my CA is off the charts! ALK is 9.4 I'm also going to stop dosing 2part.
Thanks guys. This really has me upset
Do you think the skimmer is a bad idea? I'd really hate to have wasted good money. No other corals are affected at all.
How do your other corals look? 9.4 is still okay. Ca is less of an issue than alk and if corals look okay, I'd just start dosing a little less. Water changes should help bring things back to normal.
As a word of caution, always be a little skeptical of all test kits. I tend to use them more as a metric to determine stability of my tank (ie., is the reading the same from test to test or is there a big change). I wouldn't place bets on the actual analytic value of any test kit. Its just a tool to help you maintain consistency. Again it is all about how the corals are looking.
If it is just the candy cane, I think your problem is less systemic and more individual light/flow conditions.