What do you mean, "the head stinks?" That you have odor only IN the
head? All the time? Only when you flush? The whole boat smells like
waste? BRBR

The odor is primarily in the head and it is there regardless of whether the
head is flushed or not. The odor seems to permeate the rest of the boat, with
the head as the epicenter. Again, I have cleaned the head (numberous times,
and with numerous commercial products). I have pumped out the holding tank a
number of times, flushed it, and pumped it again. I have been using "Sea Land
Liquid Holding Tank Deodorant and Cleaner," pumped thru the system from the
head to the holding tank. As mentioned, all this has helped somewhat, but not
enough to suit me.

Over to you again, and thanks....