Your problem is almost surely caused by over feeding. MT snails usually don't
bother healthy plants and will usually prefere to scavenge left over food than
eat algae or plants. I like them because the hide during the day and only come
out at night. In your case the over abundence must be causing them to come out
all the time. Put a plate or saucer unpside down with a small peice of liver
under it and remove the snails that accumulate over night until their number
are down to a more acceptable level and cut down on your feeding.

Moon
remove nospam from e-mail to send to me, I grow trees in aquariums like bonsai.
I breed dwarf crayfish, great for planted community tanks. If you can get me a
shovelnose sturgeon fingerling (Scaphirhynchus platorynchus) no wild caught
please, contact me