I like to feed my fish and probably feed them too often and too much. As a result, I have lots of nuisance snails. Only one tank with MTS so far, but other tanks hold lots of other snails that could be pond snails and bladder snails. Everything originally came in as hitchhikers and spread as I moved potted plants between tanks. Size will vary from newborn to thumbnail. Quantity is unknown. Certainly 1/4 cup, probably 1/2 a cup, could even be solid 1 cup or more. I have at least 1/2 dozen tanks to clean out, maybe closer to a dozen depending on my level of enthusiasm. My ultimate goal is to make someone's tank of loaches or a puffer fish very happy.