It says on the box its harmful to crustaceans! I just looked at teh box. right at the bottom of the english section!!! Sorry! I should have looked at all the directions before I recommended it to you.. If you only had them in there a little while they should go back to normal. Any prolonged exposure (lessay a week or two) and yea something might go wrong.. :S IM SORRY! please don't be angry..
no, I'm not angry

I bought the product and then came home and saw your recommendation, so it would be my fault regardless

I read the box too, and it didn't occur to me to worry about the snails, as they aren't crustaceans, right? But that's what the aquarium store guy'd said, and I couldn't find anything online so far that says anything bad about it, so I thought I'd put it out here.