I actually tried Esha Gastropex when some real tiny Malaysian trumpet snails (MTS) came in with some corydoras.
As MTS are livebearers I ended up with a few hundred.
The Esha Gastropex brought the snails out of the substrate and up the glass, I picked up hundreds, 40 one night, 40 another night and so on ..
The Esha Gastropex did not bring them all out though and I ended up completely emptying my aquarium of plants, sand and plant substrate.
The fish were placed in 2 x holding tanks.
I gave the bogwood a good scrub and poured boiling water over the wood afterwards.
After giving the empty aquarium a damn good clean I replaced the old plant substrate with new and also replaced the old sand with new.
The only real way to get rid of pest snails is to completely empty the aquarium and start again.
If you can pick out the ones that you can see then maybe you'll save yourself a lot of time (and money) later on.
All the best