Ok, after dealing with this issue in the past, I would like to voice an opinion as well. With my snails, I would pull out 20 a day and still not get rid of them, it was a never ending battle. Some suggested salt, some suggested different animals that would eat snails. All could work, but then someone set me straight. They told me this:
Do Not use salt, Do Not introduce animals for a purpose that is temporary that you may not want in your tank other than that purpose, not even assassin snails, they eat 1 snail a day, they will not fix the problem unless you have an over abundance of them as well, then what after the pond snails are gone... This is how you get rid of them, STOP overfeeding your fish, do a good gravel cleaning to get rid of all the excess food that is already down there. That's it!
So I did that, now instead of 500 in my 55 gallon, I have 20, I am fine with that, I can pull those out if I ever decide to, but I like them there to clean up "MY" mess of overfeeding, I still do it sometimes, I saw the population creep back up again once, so I followed the advice once again, and it worked a 2nd time. Oh, and they don't seem to eat anything but the biofilm and detritus in this tank, no plants for me,
http://i57.photobucket.com/albums/g212/Ozydego/55 gal freshwater hightech/fts101411.jpg