The thing about copper is that.. When the ich hatch out from cyst and go free swimming.. It will die immediately as there's copper in the water before it can even attach itself to the fish. Even if it manage to attach to the fish.. It will fall out aft 3 days after eating its fill and when it fall out it will either die from the copper before it can encyst.. Even if it encyst and burst out again.. It will again be in contact with the coppered water again. So yup.. Copper is the way to go for qt. Sent from Singapore Reef Club mobile app