Just thought I would get in on the "Head Odor Issue." We have just purchased an 87 Hunter 31 and the previous owner has replaced all the hoses on the holding tank and the head. But we still have a very bad odor in the head area and holding tank area. I am not real impressed with Hunters' better idea of making the holding tank part of the liner of the boat. So if I wanted to replace with the Lectr/Scan, it will be a project, I don't know. Not sure when the previous owner replaced all the hoses, but he did use the "Good White Stuff." Only thing I can see that can be replaced is the vent hose. It is the regular vinyl clear hose stuff, very soft and old. So am going to replace the hose and try some new chemicals. If anyone has had similar problems please speak up. ThanksHolding Nose in St. Louis