Showtime305 wrote: I wouldn't risk it. Just keep that powerhead for your QT and use/buy another powerhead. Carbon will remove copper from the water, but it may be at a rate slower than the powerhead may release it. I know there are test kits that allow you to test the coppers level in the water. You can try running it in a bowl or container with clean water and test it to see if any copper is being released into the water from the powerhead. If it is, keep testing and changing the water in the bowl until it stops.