Abstract: A production tank with a tank body has an oil outlet and a water outlet in combination with specific gravity valves. A specific gravity valve is mounted to each outlet. Each specific gravity valve has a floating valve member, a valve seat associated with the valve member and a valve member retainer. The valve member retainer retains the valve member and permits limited vertical movement of the valve member between an open position, away from the valve seat, and a closed position where the valve member directly engages with the valve seat. In the open position, fluid may flow through the outlets and, in the closed position, fluid flow through the outlets is prevented. On the oil outlet, the valve member retainer retains the valve member above the fluid outlet and, on the water outlet, the valve member retainer retains the valve member below the fluid outlet.