Catasetum, Cycnoces, Clowesia, and Mormodes all have similar culture. The person at the nursery only told you half the story. They do need constant moisture, but only when in active growth and until they lose all their leaves. As the growth nears maturity water is gradually cut back, the plant will then loose all of its leaves. By this point watering should be stopped and none given for several months until new growth starts.
There have been a few threads/posts recently discussing this family of orchids, their culture, and care:
cycnoches care. please help me help my cycnoches. Cycd Wine Delight "JEM" http://www.orchidgeeks.com/forum/gen...e-project.html