When I first began prescribing this approach to boatbuilders, during new-build or refit projects, I received some quizzical comments. “You want a 1½-inch holding-tank vent?!” they would ask. “No,” I would reply. “I want two of them.” Most were reluctant; some got it right away. The bottom line, however, is that it does work. Fresh air is all that’s needed to change the chemistry inside a holding tank. Even a whiff of nonaerated, and thus anaerobic, bacteria-laden effluent gas can make an entire cabin uninhabitable. Thus, an added benefit of the superventilated holding tank is a less smelly tank interior, which in turn is less likely to exploit weaknesses in the system elsewhere. In other words, if the gas in the tank doesn’t smell so bad, it’s less likely to noticeably permeate hoses and other fittings.