I just took delivery of my 1999 Passage 420. While getting her ready for the season, the water smelled awful coming out of the faucets. Our rigger suggested we drain the tanks three or four times and then put about a cup of bleach in each tank and refill them. Then run the water until we smelled chlorine coming out and let them sit for a day or two. Problem is, only the starboard tank empties before the water runs out. How do I get the other two tanks to empty? Is there a manifold somewhere that I am missing?