when i threw in some snails from a local creek for my tadpole tank, i had no idea when i released the now grown frogs, and orginal snails back into the wild, that they had layed eggs (the snails, not the frogs) and within a few days i had thousands in a 10 gal tank.
i didnt really have the heart to commit a genocide, so i'd lay the top or a sour cream container in the tank, put some food on it, check on it in a couple hours, snails will be convered on it, lift the lid and with the snails out, and then i'd release them, but after 200 trips to thr creek, i got tired and just brought the whole tank with me and dumped them out
of course you might be in favor or genocide, i dont blame you
but try the food on lid method