Seachem CupriSorb

My copper test kit finally dropped to zero after three days of running this in my filter, and I didn't even have to do a water change to get there. The resin beads turned a darker blue as they worked, which was oddly satisfying to watch.

Tossed this in my filter after treating a sick fish with copper, and within two days my test kit showed zero detectable levels. The chelating resin grabs every form of copper, not just the free ions, which is exactly what I needed.

I was worried about copper from a new decor piece, but this resin cleared it from my tank in just two days. It's satisfying to see the media darken as it pulls out the heavy metals. My fish are looking much more relaxed now.