Hello Red.

If you'll go to the top of this screen and do a search for "snails and copper" there are a few threads there that might be of interest. Although copper can be deadly to inverts some traces of copper are necessary (from what I've read). I don't know that the amount of copper in the food would be enough to be harmful or not. Until we find out differently it's best to be safe than sorry. If you have been using the food with some copper in it for a while and you aren't seeing any harm....
Snails love cucumbers and zucchini. Zucchini has
calcium which is great for snails as well. They also like algae wafers/ tablets.
I feed my snails sinking shrimp pellets also. I don't have the canister the pellets came in so I can't say what the ingredients are. I like to put my food in plastic zip lock bags. Too, I've requested a response from SWilkins as she raises Mystery Snails

Have a great weekend!
Ken

I'm going to do as you have done and stop using the shrimp pellets and just use the veggies and algae wafers until we can get more responses.
Ken