Dude, I know how you feel. I'm having an Ich situation myself. I already lost one of my big, beautiful Columbian Sharks to the damned disease. It really looks as though someone took a salt shaker to my fish!! And the plague ain't over yet. I agree with AndyL, I'm boosting my temps gradually, so that they'll fall off. And thats where they are most vulnerable. I'm sure a high quality freshwater salt would'nt hurt the little loaches either. If I were you, I'd be careful with those water changes though. They can do greater harm than good. Those sudden fluctuations in water pH levels are dangerous to fish, even more so to delicate loaches. I'm using a med. right now, its called "Jungle Ick Guard II" Its safe for scaleless fish, cause I still got a couple of sharks and 2 cats.
And did you introduce anything to your tank recently that you think had the parasite?
R.I.P. "Big Boi" My beloved Columbian Shark, never harmed a soul...