<a href=showthread.php?s=&postid=12071930#post12071930 target=_blank>Originally posted</a> by TWallace
Mike, I think you're making too big a deal of the copper listed in the ingredients. If there was any significant amount of copper in it, there'd be a lot more people on this thread mentioning dead inverts (not just snails).
I myself only had trouble with snails and Tech M when I boosted the level in my QT very quickly (like several hundred ppm in a few minutes). I forgot that I had a couple of astreas in there and saw them struggling. They were falling off the glass/rocks and were clearly not happy. I tossed them into my refugium of my main system (no acclimation) and they immediately recovered and are doing fine now. The reason I boosted it quickly is that I had just purchased a goniopora with some bryopsis on it and didn't want to add it to my main tank until it had been subjected to Tech M for a week.
At the same time, I had 2 scarlet hermits in the QT and they didn't mind at all the quick change from Tech M. If it was copper that caused the adverse reaction in the snails, it would surely have affected the hermits as well.
I never had anything die after dosing Tech M in my main system, just some softies lose their color temporarily. I kept my main system at around 1650ppm to treat bryopsis for a couple of months, boosted solely with Tech M.