Once Ich is eliminated it is gone, it will not reappear regardless of stress or anything short of reintroduction of the Ich to your system. Hyposalinity is an effective treatment of Ich, but it is not an instant or even a quick treatment. Your fish will need to endure the itch utill the Ich enters its next segment of its life cycle. If they now appear as white spots they are at the tomont (reproductive) stage. Preceding that stage they were not visible but were embedded in the tissues, eyes, and gills of the fish, that is the actual parasite stage. The third stage is when the tomonts release their tomites, which is the free swimming stage of the Ich parasite. The Ich tropants are killed by hyposalinity when they are on the fishes surface (not embedded below the skins surface) and when the tomites are free swimming. Fresh water dips is not considered s effective as many tomants are embedded under the skin. Plus fresh water dips are known for causing delayed mortality (deaths) of the host fish. Copper treats the Ich because it poisons the Ich, just as it poisons the fish but to a smaller extent. Copper would also be absorbed by your tank, live rock and any ocean sand in your tank.
The full cycle for Ich is very short at temperatures above 80 degrees, which you provide. At temperatures above 85 to 90 degrees the reproduction actually stops. Temperature conversions: C = (F - 32)/1.8 therefore, 80 = 26.67 degrees C, 85 = 29.44 degrees C, 90 = 32.22 degrees C
