It is uncertain to what snails you are referring to by 'pond snails'. That is one of the problems of common names, versus a scientific name (or better yet, pictures!). If the loaches are not eating them, you can always use the bait-and-trap method (container with bait such as lettuce or others inside), and patiently remove as many as possible each time. Not a fast method, but if you are persistent, you will be able to make a major dent in the population, and even fully get rid of them. Assassin snails (genus Anentome (=Clea)) are another possibility. Regardless, you may want to look into why they are proliferating so much, such as the possibility you are overfeeding in the aquarium.
Trap them. Cut the top off a plastic bottle (about a third of the way down), fill the bottle with a few lettuce or spinach leaves, invert the top and put it back on. Sink this contraption into your tank overnight. You'll be amazed how many snails are in the trap by morning .
You put a container or trap in the fish tank, have enough opening for them to go inside. The trick is to make them congregate on that container. Putting food will surely do the trick. You can remove the container once it has enough snails in it. Then get rid of the snails.
One way of trapping snails without actually using containers and the like is to use lettuce. Lettuce is a snail-drawer.
Pond / bladder snails will breed profilically if there is plenty of food sources.
If you overfeed your livestock and leave plenty of leftover foods in the tank then the snails will happily munch on this and breed aplenty.
But if the food source is scarce as if you are careful regarding feeding then the snails won't breed as quickly or as many, well in theory anyway.
As few people have already mentioned there are simple DIY trap methods that DO work and assassin snail is a nice option but would advise only one assassin and this will help get your snail population down, very slowly but every little helps. If you get two or more assassins, chances are these will breed too and then you would end up with too many assassins!
Having said that, pond / bladder snails do have their uses in aquaria as they are natural clean up crew for leftover foods and debris in the tank and help to clean a little bit of algae that you and I cannot see.
Also I think they are a natural addional livestock interest for the aquarium, so I actually quite like having snails in my tanks so I've never really tried to get rid of them to be fair.