If what you had was a parasitic infestation, which it sounds like you had, a really bad one, then leaving the tank fish-less for 8 weeks, will solve the problem. The parasites need a host to further their own kind. They have a life cycle, with a few different stages, the last of which is the one that attacks the fish, and reproduces. If there are no fish to attack, they don't get the needed fuel, to reproduce, therefore ending the whole colony. The parasites already present will emerge to find nothing to feed off of, and die, before getting a chance to reproduce....ending the cycle.
Hope this helps you with moving forward.
From your description, in the original post, it sounded like either ich, Oodinium, or Brooklynella. All of which are parasitic infections.