Just for kicks, I looked it up online to see what they'd do for a human with copper poisoning, and it mentioned activated charcoal to get as much out of their system as possible. If you don't use activated charcoal in your filtration, or if it's old, you might consider changing it just to ensure there's not ANY more copper in their current water.
Another thing I read is that copper poisoning (in humans) impairs calcium absorption. Since calcium is so important to our snails, I'd recommend very aggressive calcium supplementation, using snail jello, calcium 'licks' in the tank, etc.
Again, I don't know if any of this will help, all I can do is read the biochemistry stuff about humans and make educated guesses. There's a bunch of other stuff in there that I didn't understand - if any of you are nurses or doctors, maybe you can figure out other options? (I don't think Dialyses is much of an option... ;-) )
Another thing I read is that copper poisoning (in humans) impairs calcium absorption. Since calcium is so important to our snails, I'd recommend very aggressive calcium supplementation, using snail jello, calcium 'licks' in the tank, etc.
Again, I don't know if any of this will help, all I can do is read the biochemistry stuff about humans and make educated guesses. There's a bunch of other stuff in there that I didn't understand - if any of you are nurses or doctors, maybe you can figure out other options? (I don't think Dialyses is much of an option... ;-) )