4-Gallon Salt Feed System with 12VDC PumpThe 4-Gallon Salt Feed System with 12VDC Pump is designed for boats that operate in fresh or brackish water and can only be used with LectraSan; MC™ or electro-scan; Type I MSDs. Salinity is monitored by the unit's Control Panel and salt solution will automatically be added to the MSD when needed.Pressurized freshwater is required. Minimum of 15 psi (103 kPa) working pressure.OperationSolar salt is added directly to the tank. Water supplied by the boats pressurized freshwater maintains the water level in the tank and continues to make saturated salt solution from the solar salt. A pump is used to add salt solution directly into the treatment tank when needed. The pump is controlled by the circuit board that monitors the electrode current in the treatment tank and automatically turns on the pump when salt is required.