I dress almost every salt pattern with Saltwater Krystal Flash, and have for years. Although it doesn't say so on the package, ALL the Saltwater variety is GITD. Lately, I've added a few fibers of the UV to the mix. I firmly believe the added spectrum visibility helps in all light conditions, and I will guarantee it doesn't scare fish off! Every northwest diver will tell you how much bio luminescence there is in our water, so it stands to reason most of our species key in on it.
I don't bother to "flash" the flies anymore, and still get lots of strikes in low light.