Do you keep any snails instead of your aquarium on purpose (no accidental hitch hikers, etc.)? If so what species do you keep in their and what is your reasons for doing so?
I personally keep inside all of my aquariums Malaysian Trumpet Snails, as they not only mix up my sand substrate but tend to eat away any algae that is growing along the glass walls. My favorite aspect of them is that they burrow during the day so it appears as if there are no snails inside of the given aquarium. During the night however, they come out and eat anything that is left over while leaving any fish, other invertebrates, and each other alone and then disappear under the sand before I have my lights set to turn on in the morning.