It looks like I'm not the 1st:
http://www.livingreefs.com/forums/saltwater-aquarium-articles/590-use-vitamin-c.html
I highlighted a few things that stood out, pertaining to most of our common problems with zoas:
-Beneficial to most corals on which we have tried C. Corals appear to open more and look more vibrant. Although one could easily construe this as subjective, the impression of others who looked at the tanks over a period of time were positive in this regard.
I am definately finding this to be true, with my already healthy corals!
-Enhances colors in fishes and in corals, especially when used long-term.
-Prevents, to a large degree, bacterial infections from spreading rapidly and becoming sores on the body of fishes, or
affecting corals to to a degree that they start to "melt", or liquefy, or taking on a toothpaste appearance, as some hobbyists call it.
What Vitamin C, combined with water directed at the infected areas, does is prevent the spreading of the bacterial infection and promote the healing of the coral and or the fishes.
This fact has been related by many hobbyists. To clarify this further:
when bacterial infections spread on a coral, the polyp tissue starts to disintegrate (turns whitish like a toothpaste like material), or a brown type sludge emanates from the coral polyp. Both are signs of bacterial infection.
Statements in bold, are the exact decsripton of what has been happening to my zoanthids for many years.