I've been trying to develop a line of Blue Ramshorns and Red/Gold Ramshorns (different tanks). I find the best way to control them is to try to breed them. Seems like when you want baby snails it just don't happen.
When you have to many put an algae wafer in a fish net and leave it the tank over night. In the morning remove the net full of snails. Return the ones you want back to the tank. Really just that easy.