i believe all snails are hermaphrodites (some species are capable of asexual reproduction) so you can keep only one if you wish them not to multiply, and in the case of the asexual reproduction you cannot stop it short of sterilizing the snails.
as far as the eggs go removing them from the tank and smashing them would be a good start.
as far as the eggs go removing them from the tank and smashing them would be a good start.
