I was gonna post this as a reply to the invert killer thread, but I though I would just start a new thread and get some ideas:
There has been a running theme of Cu contamination around here lately. Has anyone ever read about treating a tank with EDTA or some other metal-chelating agent to get rid of any trace Cu that might be adhering to the tank? You would want to do it while the tank is empty of anything living, as EDTA will also chelate Ca and Mg and other "good" metal ions, but the thing about EDTA is that once it has chelated to the metal ion, you can just wash the EDTA-Cu complex away. And since reefers usually add PLENTY of calcium to a tank, it wouldn't really matter if there was a little left over in the tank, it would disappear after a few water changes.
The EDTA might also "draw" the Cu out of the glass and silicone etc, as it would bind up free Cu and then the equilibrium would reestablish itself, releasing more Cu from the glass/silicone etc into the water. I could imagine soaking a tank in a solution of EDTA (for days, possible changing the EDTA solution a couple of times?) as a way to clean the tank before setting it up.
There are also other metal chelators out there, EDTA is just the most common. It is used for lead poisoning (you actually drink a solution of EDTA, and the EDTA-Pb complex is excreted).