+1 Vermetid, take them off of the base (scrap them with tool from the LR), don't cut only the top part of the tube, they hide in the inner tube - spiral like (this one need to be destroyed with the snail in)! If can't take it out of the water, at least try to smash it completely with something metal.
Oh goodness. Well, since I do not have any fish yet, should I just drain the tank and start over? Will ‘airing‘ out skill the snails? Or if I replace with fresh RO water will they be gone? How long do I wait?