Also, have copper in the tank when you don't need it does harm, not good. Its not good for fish or corals to be present all the time. Just when you need it should it be in the tank.
There is merit to B-Balls post. Copper used constantly can cause liver damage and other problems not the least is that your tank will never be safe for inverts. Depending how long you have beed doing this will be the key to whether you can ever get it out enought to sustain other forms of marine life. I would start to remove it by water changes asap. The best way to prevent disease is good maintenace practices and good fish selection with stress free living for them.
Keeping your tank water clean, meaning low nitrates reduced by water changes, not overcrowding, and quarantine all additions. Are you treating for something now? I noticed your other post about adding an angel, dont do it.