I am a recent owner of a retail aquarium store, my partner has been in this business for over 30 years. We use ICH-X in all of our systems with fowlr and all reefs. From what I've learned, ICH lies dormant in every system and comes out due to stress and a degrade in water quality. Remember ich can come into any system a numbers of ways, live rock, corals and fish. So it is best to feed with a little garlic, you could always raise the temp on the tank a few degress and lower to salinity for a week or 2. That has also helped many of my customers.