[genieskip]

I couldn't agree with Valiente more. That's why I just junked my heads, pumps, valves, holding tanks etc and installed a couple of composting toilets. Less smell than I had before and incomparable simplicity with the only moving part a bottle for the "liquid" to be taken on deck and poured overboard when offshore. And the "found" space of two 20 gallon holding tanks moved to the dumpster. Simple is best when offshore!