The use of copper

[sky]

I've been feeding my fishes w/ garlic guard, I did try to give them a fresh water bath, and I don't have a hospital tank running. I thought copper isn't a chemical but just a natural element which even exists in our tap water but in a very low level. Since I'm not adding chemical/medication to contaminate the water, I don't see how bad it does to the rocks beside killing the worms or those tiny creatures living on them and once the copper is diluted, it should be fine to the system because it's natural, isn't it? The reason I intend to add copper into my tank directly b/c like I said I soaked the rocks into a freshwater bin w/ copper for almost 2 months, but disappointed enough to see the ich are still on some fishes...so I suspect they may hide in the gravel, somewhere in the tank or filter beside in the rocks. I'm so fed up and my ultimate goal is to get rid of all those ich that are hurting/killing my fishes and my only concern is whether if copper will harm the nitrifying bacteria and break the biological cycle in my filter, can anyone tell me? and I heard some stores leave copper in their systems to prevent the outbreak of disease so I wonder if I can leave copper at a safe level in my tank as well?

Anyway, thank you all for the quick responses, valuable info. and advices.