She's very open with sharing her knowledge but you should buy Peggie's book. Money well spent.
As much as I appreciate your recommending my book to him, and as much information in it that I'm pretty sure he needs, it doesn't include the answer to his question 'cuz marine toilets don't work that way. But I'll be glad help him get it all sorted out and working the way it should. The first thing he needs is the owners manual for his toilet and I can post a link to it as soon as I f find out what what he has.
My boat is in salt water. For regular use I do NOT use salt water in the head. If you flush with salt water and that sits in the holding tank, the tiny critters in the salt water will decompose and start to smell.
It's not in the tank that salt water starts to stink, it's in the toilet intake line, pump and channel in the rim of the bowl where micro--and not so micro--organisms in sea water die, decay and stink. There's a simple way to solve that problem that works on most boats that have head sink drain thru-hulls below waterline and on which the toilet and head sink are on the same side of the keel:
Sink drain thru-hulls are below the waterline on almost all sailboats. So re-route the toilet intake hose to tee or wye it into the sink drain line as close to the seacock as possible because the connection must be below waterline to work.
This will allow you to flush normally with sea water. After you’ve closed the sink drain seacock in preparation to close up the boat (you do close all seacocks before leaving the boat to sit??), fill the sink with clean fresh water and flush the toilet. Because the seacock is closed, the toilet will draw the water out of the sink, rinsing the sea water out of the entire system—intake line, pump, channel in the rim of the bowl and the discharge line,(Water poured into the bowl only rinses out the toilet discharge line). If your toilet is electric, be careful not to let it run dry…doing so can burn out the intake impeller. Or you can keep the sink drain seacock closed except when it's needed to drain the sink and flush with fresh water down the sink all the time...your choice.
It may also be necessary to keep the sink plugged except when in use, with a rubber sink plug or by installing a conveniently located shut-off valve in the drain hose. Otherwise the toilet may pull air through the sink when you try to flush, preventing the pump from priming.
--Peggie
