Hey bigsteeviestyle, I've had the same snails in the past, both on algae eating snails and on clams. I am very fond of biological controls, like coris gaimard or sixline wrasse (forgot--pseudochelinus??), that will actually eat them. A couple friends and I have talked about them, and done a little research. Most info suggests that they don't move over substrate or glass, but only on clam shells. I have a hard time believing this, as the snails seemed to infect other astrea and trochus in my tank, both at the same time, when at first it appeared only one species was infected. This doesn't exactly correlate to the information I've found, but as we all know, much new information in the hobby is spread through individual hobbyist experiences. I usually remove the tiny 5mm or so snails by hand in a seperate container of saltwater, and hope that my coris does his job, which currently he(she) is.
