Nobody said that salt couldn't kill ICH, but being that we were talking about brackish conditions that contain salt, it is pertinent to say that in that environment, salt will have little to no effect. And comparing organisms living for millions of years to improperly caring for terrestrial plants or the composition and salinity of the water is a little extreme. And yes, put anything in a PH of one and damage will most definitely occur, but that is an example of an extreme. With that said, I will revert to my precious post, a slight change in any parameter will not kill your fish, but it most likely will not cure the problem of ICH either. Any extreme that will kill the protozoan parasite, will most likely kill your fish as well. I'm all for finding things that are non chemical treatments, but for the most part, there is little that works quicker than a chemical treatment. For example, raising the temperature will speed up the life cycle of ICH, but unless supplemented by another treatment, it only speeds it up. Raising the salinity rapidly will kill the ICH but would also most likely kill the fish. And if you did do it slow enuff where the fish could endure the change, who's to say the ICH cannot acclimate as well?
I guess all I'm saying is not every home remedy works, and not ever commercial treatment works either. Use what is best for YOUR particular situation. I myself have been lucky enuff to not get ICH in my main tank, but if I did I would have a handful of problems being that I have a gymnothorax tile, who do not do well with formalin, methaline blue, malachite green, or any other anti parasitical treatments available. Same situation in which this thread was about, having loaches or cories, whichever it was.
Anyway it's late, I'm tired, and I will actually read what I wrote when I am fully lucid and conscious. Hopefully I made sense tonight lol. If I didn't I apologize.