From experience, DO NOT USE THIS METHOD.
I always like to go one step further, and thought, right, if 12 volts can kill snails, 240 will do a better job, I know DUM and DUMBER
But the snails died and so did my scaless fish.
From the oxidization of the copper.
Now we all know that copper kills snails, but in most setups, too heavy a dose, isn't good for the rest of the inhabitants.
Try a piece of lettuce, weighted with lead around the stem, attach a string to the lead for removal of the trap and lead. The lettuce provides food for the fish and snails
I set this method overnight, and remove it in the morning, carefully, and dip the trap into VERY salty water. This kills the snails almost instantly, and then if there is enuff bait left, reset it, or replace the lettuce.
Cost ZILTCH
Success, HUGE
Snail population, LOW.
Alan 104