Just add a few cons. I just put some into my tank that had a huge snail problem. Next night i notice every snail was gone. I mean their were snails allover and now nothing. Must of thought it was food? Cuz i don't even see shells.
I only have snails in my betta tank, my cichlid tanks are snail free (even though I keep putting them in them), there are a bunch of shells, and shell fragments.