The easiest, cheapest, and most sure-fire way to get rid of snails is a potato cut in half and leave it in for at least an hour. Pull it out with snails attached and throw them away. Do this for several times, and eventually you will get rid of them all. Cucumber does not work as well for a few reasons. One it doesn't sink, and two it does not attract snails as fast. Clown loaches can work, but often do not, and are not a long term solution. Copper will work, but will also wipe out your inverts, plants, and bio-filter. Salt is another option, but will again affect inverts, and plants. Larger snails isn't a good option, as the larger snails will not outcompete all, and you still have snails.