You will reduce the snail population if you don't overfeed the fish. Snails breeding 'like crazy' is a symptom of overfeeding usually.
If you want to get a lot of snails out at one time, the easiest way is to pick them out by hand. You can get them to congregate in one are by putting something they like in one spot when you turn the lights out. Take a slice of squash or cucumber that you microwaved for 5 seconds or so to soften it, and weigh it down with a plate. A few hours later, you'll find a lot under the plate, eating in the 'cave' you provided them. Sinking pellets work well to, but with the fish you have in there, they will likely go after pellets under a plate too, so that's no good.