LFS sold me Cupramine for ick

It is a good medication, but it should be used in quarantine, not in the main tank. While seachem claims that there is no absorption by calcium carbonate, I am not sure if I believe that there is none. Maybe less, but no absorption at all is unlikely. I know other chelated solutions will still be absorbed, so I doubt cupramine is much different in that regard.. I hope you didn't treat a tank containing any live substrates (rock, sand, etc) because it will kill many beneficial organisms. Personally, I wouldn't use the materials with invertebrates again.

Yes, I have used it in both home and shop settings and found it to be very effective and does not make a tank useless for inverts later on either. Although I would recommend a complete water change and then run Cuprisorb with the new water just to mop up any remaining copper treated water left behind in the rock and sand. A copper test kit is a must have item as well.

Chuck

Charles, I respect your opinion and experience, but mine is conflicting. I had repeated the same thing with cupramine when I first started and had issues with inverts for quite a while until substrates were replaced. I even use cuprasorb. I would do more than one complete water change--I would give it a good long while (and multiple complete water changes later) before I would put invertebrates in there. The damage is done to the live rock, already, however.

I should have made note that any live rock will see a massive die off and took it for granted that would be a given and known. Any such live rock or live sand for that matter, should be removed and kept outside of the tank during such a treatment. Again, I made the assumption that this is a fish only tank with just base rock and sand, for an established tank with live rock and/or live sand, I would never treat the tank with anything at any time.
Besides having done so myself (base rock/sand and no inverts or bare tanks) in shop settings as well as having others do so with no issues of using the tank, base rock/sand again, I would say its a "can be done" thing. Under the right cirucumstances. Although, I doubt I would ever find any tank of mine in such a "bare" situation that would allow me to cupramine treat it, and would do such things in a QT setting.

Chuck