The only purpose of the water or sand is to regulate your temperature and keep it constant. Atleast that is what I always was told. I use water during the summer and PLAYBOX sand during the colder months. Those that think the water is keeping their food moist are admiss, although it does help alittle. Water also cools faster and will evaporate, where sand is there thru the whole smoke, also allows you to maintain higher temps easier too.
