IME they don't seem to be bothered by it a bit, but it may depend on the type of snail and the difference in water parameters. Most common snails are pretty tough.
Everything is the same except the Nitrates are 15-20 ppms higher.
Will they make it? They are on the plants that I am adding to the tank from a different tank I have. I'm pretty sure that they are Ramshorns.
What kind of snails. IME my pond snails can take really bad water. I was testing some stuff and cycling ideas and the water was like ammoina: 4, nitrite: 3, nirtrate: 80. It was in a extra tank that I cleaned out but some snail eggs must of made it througt.
snails are very tough as a general rule, tank changes ph changes,emp, polltiun etc don't bother them much if at` all. other than excessive heavy metals they are reasonably bullet proof.
Dave