The ONLY way of getting rid of pest snails in ALL kinds of setup is using 'Flubenol 15'.
I speak from experience as I have the most awkward setup for dealing with them, i.e. a SMALL Jewel Rekord tank (with horrible internal filter system), planted with fish AND shrimp.
If you have a Juwel tank with the internal filter then the snails will also be infested into the media sponges themselves and no amount of snail chomping fish will rid a tank of them simply because they cannot get at them to eat them. Secondly they don't eat the eggs and like you say, if you have a small tank or are currently overstocked then you can't use them anyway.
Flubenol is NOT based on copper & the added advantage of this is that it is safe with inverts (i.e. shrimp) & crusts, and is also safe with fish, plants and filter bacteria. It is nigh on impossible to overdose as it is OK up to 10 times over the recommened dosage.
Now, it won't kill the eggs, so when getting some, £3.50's worth for a sachet of 4 grams, is enough for a ONE off treatment of 100 UK Gallons.
Divide 4 grams into 5 equal parts and store separately (this means that 1 order of 4 grams can treat up to a 20 UK Gallon tank). Then once a week AFTER your usual water change (for now & then for 4 weeks thereafter) pour some into your tank after mixing it in a mug of tank water (the tank water will go cloudy for about an hour, but this is fine).
4 weeks later, BOSH, no more poxy snails.
You'll notice no difference in snail behaviour during the first week. (Continue to pick them out - DO NOT CRUSH THEM IN THE TANK AS THIS MAY RELEASE EGGS).
During the second week you'll notcie they'll get sluggish and start congregating at the water's edge.
At the end of week 2, after usual water change, if you vac at the same time you'll notcie that you are vaccing up empty snail shells.
It will take about 3 weeks for them to totally disappear.
Keep going to be 100% sure of 100% snail eradication EVERYWHERE in your tank.
The continual dsoing will take care of any hatchlings from eggs during the dosing period.
GL
Andy
PS,
If anyone mentions snail traps, 'puffers', the 'cucumber trick', total-stripdown-&-bleach-clean, I will flay the man/woman flesh from your puny frames!