snails aren't gross.. theyre beneficial IMO, cleaning detrius and uneaten food, as well as grazing on any algae.
you can:
remove them by hand at sight
place a blanched piece of lettuce in the bottom for 2 hours with lights out.. come back after 2 hours and it should be covered in snails.. repeat as necessary.
get a loach or puffer and add to your bioload.
use harsh chemicals which will taint your tank permanently and kill ALL inverts living inside, to include shrimp, clams, crabs, crayfish, and the like.