[Witfull]

copper is a dual edged sword, it kills parasites better than anything, but it is adsorbed quickly into just about everything, including living tissue.

as for reusing a tank, yes it is possible. copper that is adsorbed into the glass and silicone isnt acted upon by biological and chemical breakdown. so basically it is locked in. and any that is slowly released will be of extremely low concentration.

rocks, gravel, and other items that are effected by erosion, either biologic or chemical will release copper is higher levels. sand beds as they are stirred, they grind against each grain releasing smaller particles. sand and rock also is affected by pH and bacteria. pH is lower in a sandbed and within rock, as we know, so as it erodes the good and bad are released.. bacteria uses ensymes to breakdown waste, and the sand and rock is broken down in the prossess, releasing the copper, and bacteria tugor pushes it into the water columb.

also concerning sandbeds, sand is ingested by many creatures. as they do copper becomes bound within their matrix. over time levels within their bodies will rise finally leading to toxic levels. for example, bacteria breaks down the sand and copper gets into the diterus, pods feed on this, before it get to a toxic level for them they are eaten by fish. the fish adsorb the copper internally. the copper is drawn to the liver and kidneys as the body tries to filter it out. in time this will lead to organ failure and death.

another problem is copper kills everything including bacteria, so it will effect the biobed of a tank as it is released.

because of these issues, it has become a "rule" to not reuse copper treated items. the risks out-weigh any benefit.

these are my thoughts on this.