[Haloreef]

I use the gel. In one of the tanks I kept I had the Monti nudis also. I quarentined the monti and super glued over any spot that showed damage. I did this every night for aprox. a month and ended up saving it. Interestingly enough it was also a pink Monti. You have to check every night some nights every thing would look fine and then I would see a white spot... more glue!
I have not found, or read about, any dip that will kill the Nudis and leave the coral alive.
If you are not prepared to do this night after night you may want to toss it. It depends what this coral is worth to you.
Once again good luck!