Hey guys, Having trouble on a 60 Hatteras M/Y with the black water holding tank. Just hopped on board and the owner has told me that the tank will not pump past 50%. She had been sitting over a year before going on the hard where she currently rests. I believe there must be a great deal of sludge-like buildup that has accumulated. This week I plan on adding in a mix of water softener powder, laundry detergent, and bleach. Along with that I have ordered some enzymatic additive to toss in as well. Since the boats on the hard and I have yet to go off-shore and test out the O/B discharge, I was planning on letting that concoction sit for a few days, adding water periodically, and then eventually getting a pump-out truck to the boat. I figured I would pump the hold and then flush the entire tank multiple times with freshwater to see if I could get most of the crud out. Any suggestions or revisions to this game plan would be certainly appreciated! Also, I plan on using minimal bleach as I would like to avoid eating any weak seals... Thanks guys!