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.
Good luck!