The 4-gallon salt feedwater system with 12VDC pump is designed for small boats operating in fresh or brackish water and can only be used with LectraSan MC or electro-scanning I MSD. The salinity is monitored by the control panel of the device, and the salt solution will be automatically added to the MSD when needed. Need pressurized fresh water. The minimum working pressure is 15 psi (103 kPa). surgery. Add sun salt directly to the water tank. The pressurized fresh water supplied by the ship maintains the water level in the tank and continues to produce a saturated salt solution from the solar salt. When needed, use a pump to add the salt solution directly to the treatment tank. The pump is controlled by a circuit board, which monitors the electrode current in the processing tank and automatically turns on the pump when salt needs to be added.