As a fellow 34DC owner Welcome! Not to many of our "little" boats out there. As far as the black water system goes I am in the process of converting the existing freshwater tank to a blackwater. I had a new 120 gallon freshwater tank made. I gutted mine down to the bulkheads and started over so I won't be much help with the original side of things. Enjoy your trip into insanity i'm still enjoying mine but it wasn't a long trip for me.