Q tanks are not treated with meds (other than adding a bit of salt). They're simply used to observe new arrivals prior to introducing them to a community. When you add treatments it becomes a hospital tank. What fish are you planning to treat? Do they have ich? If so, have you already tried raising the temp above 82F and adding salt? Keep in mind that these meds can cause serious liver damage to some species, burn scaleless species, and outright kill inverts.