Copper
 

Long story short, I have a 24G Nanocube currently set up as a FW planted tank that I want to turn into a reef tank. The tank has been dosed with a fertilizer that contains copper. How can I safely clean the tank and remove the copper so that it can be used for a reef?

You can run carbon to remove the copper from the tank. Pick up a good copper test kit to follow the progress of the copper removal.

What about using something like Cuprisorb? Or will that only absorb the copper from the water column?

You can use that as well, as I mentioned before, just make sure you get a good copper test kit. After the removal of most of the copper you will be cycling the SW, so by the time you are ready to put in corals and inverts there should be no cooper present (assuming water changes as well). With adding fish (if you put them in first) even if there is still a bit of copper present they should be fine.

A good vinegar rinse out helps as well for the Cu bound into Ca on the tank itself.