Does Copper Nuke Cycled Media?

[Aaron-A2]

I have (2) QT tanks with sponge filters that were cycled from sitting in my DT sump. If I add copper, will that completely nuke my beneficial bacteria? Are there other common medications that could also wipe out beneficial bacteria?

 

[JoshKReef]

Not fully nuke, some will die, some will adapt.

 

[Halal Hotdog]

One way to help breed the resistant bacteria is having a QT constantly running with low levels of copper, that will help eliminate any bacteria that have no tolerance for copper. CP is a great medication for QT as well, however that does nuke all beneficial bacteria you may have. It is also milder on most fish than copper.