I can’t advise on the treatment, I personally never had to deal with much as far as sick fish in years . But if HumbleFish said it’s good then I would go with that. He is really knowledgeable. Ten gallon would be a bit small for tangs.
Depending on size of fish the yen may work. The 75 is large and would take more medication if that’s the route you go. But you can set up with fresh salt water and monitor ammonia and do water changes as needed, I do my seahorse fry like that early on . Change water daily .,that site I referred you to HumbleFish is good place for treatment protocols