First thanks to Peggie for helpful comments from a previous post about replacing the holding tank. As with most projects this one is growing, but it is growing out of the desire to do it right the first time (rather than the desire to lighten the bank account). I am replacing the holding tank, all hoses and am now planning to replace the 15 year old toilet on my 1990 35.5 as well. Peggie recommended, in another post, the Raritan SeaEra. In reading about the contribution sea water can make to head odors, I am intrigued by the idea of using 20 gal or so of my 65 gal of freshwater on a cruise to flush the head. The questions are: are there any advantages to the electric macerater heads vs. manual pump heads in terms of longevity, maintenance, odor? Is it mainly about being able to push a button vs pumping? Does 65 gal: 20 gal seem like a reasonable fresh water: holding tank ratio or would I be better off sticking with the sea-water flush models (assume 2-3 days out typical between pumping, refilling the tank). I can see the safety advantages to using pressurized water and leaving the head through-hull closed more often. Finally, if I forgo the electric option, what is the best brand or model of manual, sea-water head? Thanks.