I bought the single barrel that DIGGER27 was talking about only because they didn't have the double barrel one in stock about 3 weeks ago. I've found I really don't need much more then that.
I've used it about 4 times now running for about 4 to 5 hours each time and have had zero problems with water leaking out or the belts breaking. BTW, they come with about 4 extra replacement belts.