Problem with crushing them is that it leaves a lot of dead bodies decomposing in the tank, and hence a potential spike in ammonia that may harm your other livestock.
Maybe try leaving bait (lettuce leaves?) in the tank overnight and remove the leaves + attached snails in the morning?
If you have Cory Cats, they will gladly eat the smashed snails.
40 breeder - 1.25" Dirt/1.25" Black Diamond cap - Pressurized CO2 (2.25bps) - 2x54watt T5HO and 42watt LED (total 150watts; 14,500 lumens) - EI dosing - 50% weekly WC - H.O.T. Magnum 250 canister - SunSun 530 gph pump - Set-up 7-14-2015 - Cycled 8-1-2015
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