i think both of you might benefit from the link i posted earlier. read it-you might learn how to properly nearly eliminate ich from your hobby life, and also learn why the advice you've been given is a whole lotta b.s.
fwiw-anytime anyone, including me, makes some type of assertion, look up the actual facts yourself. be a critical thinker. but use actual factual data to judge if other's 'dogma' is actually correct. i'm backed up by decades of research by many many ichthyologists, parasitologists, and marine biologists who've dedicated their careers to figuring ich out. weigh birch's statements against the scientific community's CONSENSUS. lemme know what you find
(and this is nothing personal, hope you don't take it that way).