Have your book and have followed all of your advise so far. While replacing the head last week (Raritan PH-II, SeaLand Odor Safe Hoses) I noticed the vent hose had some blockage. I traced the hose to the deck fitting and was able to remove it this evening. Now what do I use to replace it? It is 1/2 hose, it seems all of the hoses were important, I would assume this is as important to odor control as well. Any advise would be appreciated.