Andrew, I think you should attempt to fix the problem by removing all fish from your tank and treating them for Ich with either Copper, Chloroquine, or Hypo and leave your display tank fishless for 8 weeks.
I realize this is a lot of work and not easy to do depending on how many fish you have.... but you're going to spend a lot of time, energy, and money on things like water changes, uv, and dietary supplements... and the chances of eradicating Ich with those methods is very, very low.
BTW, I use Stress Coat when acclimating or handling fish. I think it's a fine product for those uses. If there are other issues causing the fish to lose their mucus coating then those issues should be directly addressed.