Originally Posted by
boozzbro
actually it will just not fast. Its science (osmosis).
The copper in the rock/ substrate will diffuse out into the water provided there is less copper in the water than there is in the rock. Eventaully when you remove water you will remove the copper with it. and over time the copper will be removed.
I stand corrected...
Given hundreds of thousands of gallons of water changes and a few thousand years a tank can be almost certainly assumed to be free of copper.
There have been reports of copper leeching out of the silcone of glass tanks. Since no one can predict the leeching timetable you run into the problem of trying to "guess" when your tank is clean.
The moral to the story is "Don't medicate your display tank". If you have made a mistake and done so, be on watch for mysterious invert deaths should you choose to risk it and introduce them.