what parasites are you looking to kill in the dip. if you have access to a microscope you can do light scraping of the tissue behind the gills to check for flukes, salt won't kill them. fish lice you can pick off, anchor worms you can pull off with a tweezers. internal parasites such as flagellett protozoa, nematodes, round worms and tape worms won't be affected by the salt either. i'm curious as to what parasites salt will eliminate.