The best method for snail control is to put an algae wafer or a piece of cucumber under a saucer at night just before lights out. In the morning, lift the plate out and a good portion of the snails will be clumped together and easy to scoop out with a net. Done a few times, this will eliminate a fairly large portion of snails.
Loaches don't do well singly, and are often kept in unsuitable tanks due to the fact that they have certain requirements, often not met by the aquarist. They are very social and need to be part of a shoal, high oxygen levels, rounded (not sharp) substrate just to name a few. Loaches should be kept because you are keen on them, not as a pest control.
I was also told to use Loaches when I first started my tanks with plants and aquired the dreaded pest snails. I quickly learned the hard way that loaches are good at chowing down on the snails, but had better success in ridding my tanks of snails with the algae wafer method.
Hope this helps some!
Tammy
) and they are the ultimate champions in snail control 
