Hi Peggy - We bought a '95 H26 last fall and knew we would want to replace the portapotti with something that could be pumped out. After reading your articles this past winter, we decided that installing a portapotti that could be pumped out was our best solution. Following is our story. It might be long, but I don't want to leave out anything important. I purchased a Sealand portable/permanent potapotti because the last portapotti was a Sealand and I didn't want to change the hold down brackets (I'm not very handy). It's the one with the 5.2 gallon tank. I cut thru the wall directly behind the portapotti so that the hoses would not kink as they came out of the head and ran up to the pumpout and vent fittings. The pumpout hose (standard 1.5") leaves the fitting at the back of the portapotti and curves upward (total length about 1') and to the left to the starboard wall (another 1-1.5') and then the ceiling of the head cabin and then striaght over and out (another 2.5', total length approx 5-6'). I had to leave room for turns because the hose is quite heavy. There are no spots where the hose becomes lower than it was before. The vent hose (standard 5/8")leaves the back of the portapotti and goes straight up 2.5' and the horizontally out. Total length approx. 4-5'. After installing the hoses I filled the tank with water and pumped out to make sure there were no leaks, and there were none. After the initial pumpout I "primed" the holding tank with about a quart or two of water (remember, the tank had yet to see sewage). About five days later I added K.O. I added to much by mistake, about 5-6 oz. to a 5.2 gallon tank, and we started using the head for it's intended purpose. Within 24 hours of use (both #1 and #2) it became stinky, although only when the flush bar was pulled, exposing the holding tank. The smell never went away over the course of our 4 day trip, although it was only when the head was flushed. We returned from the trip late and were unable to pump out and couldn't get back to the boat for 10 days. Again, it was only when we flushed, but when we did it reaked!!! We pumped out the next day. During the trip I made sure we added plenty of water to get as much dilution as possible. After reading more in your column, I see that you suggest the vent be much larger. This is unlikely to happen for me because as you may recall, I'm not handy. How can I create a better airflow out the vent (there are no kinks, the passage is clear) instead of directly out the top of the holding tank? Are there other chemicals, I should use? Or should we accept it and pump out frequently? The last option is not all that bad, but if there is something to do to improve my system, I'd love to hear it. Also, I always rinse the holding tank 2-3 times when we pump out and run the water hose back down the sewage hose to rinse that, as well. I also always start with a quart or two of fresh water in the holding tank. Thank you for your patience with my rambling and your suggestions.