You will like chloroquine phosphate, so much better than copper. Much less stressful to fish.
Ich is not always present if you never let it get into the system. Treat and/or quarantine all things going in to the tank. That means no fish in coral holding systems that could possibly hold ich, minimum of 4 weeks in fishless system for all corals, live rock, etc. Not impossible but just takes a lot of diligence to make sure it never gets into a reef tank. Once it is there it is impossible to eradicate because meds also kill corals and other reef inverts. You can keep it suppressed in most cases if stress levels in fish and parameters remain ideal, but if anything goes out of balance then it can always show up if it is there.