Gravity feed marine head.
The gravity feed Marine head is the simplest configuration. It is a head sitting above a tank. When the lever is pushed the effluent falls directly into the tank. It uses water drawn from the onboard fresh water supply or dock side water supply to fill the bowl with water for flushing. It is very similar to what is used in the RV industry. Because there are no mechanicals other than the flush valve involved it is a very easy head to maintain. But there is also no barrier between the effluent and the head opening when flushed. Without proper treatment these tanks can have severe odor problems. Typical tank treatments use a strong deodorant to combat the odor with limited positive results. Each flush dilutes the ability of the deodorant to overpower the odor. According to the labels, the deodorants must be added every 5 to 7 days or less if the temperatures go above 85 degrees. Forget About It For Boats does not use a chemical deodorant to mask the odors. The all-natural probiotic bacteria were blended together during a 30-day fermentation process that enables the beneficial bacteria to consume both the solid waste and the offensive odor. Of course, it is a lot more technical than that, but the result is solid waste and odor is gone leaving only a colored liquid in the tank. This is a HUGE benefit for a gravity feed head. When the toilet is flushed there is not a rush of foul odor exiting the tank while the valve is open. An added benefit is that as long as there is a food source (Use Your Head) these beneficial microbes will continue to multiply and repopulate the tank until the tank is full and must be pumped. This could mean months between pump outs with only positive benefits to the system and environment.