[Chris Burkard]

You will need to install a Macerator. The original option Teed both fish box drain lines together through a macerator pump and overboard. The fish boxes are too low to just send them overboard directly. Discharges like this need to be a certain level above the water-line and the bottom of the fish boxes are below waterline. If you do this yourself, make sure you follow the Coastguard guidelines for thru-hulls, double clamps, hoses and routing of the hoses themselves (you may have to loop them before they go through the hull). If you are not very mechanically inclined, I would have a professional install this system.

Good Luck!