Thank you, Peggie for your most helpful reply...

Claus
"Peggie Hall" wrote in message
. ..
claus wrote:

We have been treating our holding tank with Raritan K.O. for the past 6
months... but have not used the head much until summer finally kicked in.
Unfortunately, stinky gasses are coming out of the vent whenever we
pump....

If you haven't added any K.O. to th tank since last fall, yes...the
bacteria died. You should have thoroughly rinsed out the tank before
storing for the winter. The bacteria in K.O. are like any other living
organism...they need food to survive. So they'll die if they exhaust their
food source (nutrients in waste) while the boat sits for an extended
period.

So before you resort to more drastic measures, pump out and thoroughly
rinse out the tank...and also backflush the vent line to make sure it's
clear. Then restart it with a fresh dose of K.O. If you do this right
before the boat will sit, add a couple more ounces of K.O. with the first
flush after you return to the boat.

If you still have odor, it's because your tank isn't sufficiently well
ventilated to allow the bacteria in K.O. to function aerobically. Odorlos
is another non-chemical product that often works in tanks that K.O.
can't...so try it ACCORDING TO DIRECTIONS!!! before doing any surgery on
the system.


The vent and vent hose seem clear - since the gases come out

That's no guarantee that it isn't at least partially blocked. Tank vents
require maintenance. Check the thru-hull regularly...scrape out anything
you find...and backflush it every time you pump out and/or wash the boat.

- but perhaps
the bacteria died over the winter ...

Of course it did...it starved to death. And it may have died in the
bottle if you stored it where it could freeze or where temps went over 110
F.

- but perhaps stronger measures are called for.

Or at least reading the directions on the bottle of K.O.

What I have in mind is to install a small aerorater pump of the type that
sends the airflow through a pipe to the bortom of the tank - but I have
heard that they can be quite noisy - sort of like an aquarium pump. So I
am
wondering if you have any recommendations for a quiet pump of that type?

Aeration isn't quite that simple...there's a bit more engineering to it
than most people realize. The piping in the tank has to be able to
distribute air across the entire bottom of the tank, and it has to be
designed to prevent becoming clogged by sludge...and the pump has to run
24/7/365 to keep the tank odor free.

Secondly, if the pump does the job - and the bacteria turns the tanks
contents into water and CO2 - would that then qualify as treated waste
that
could be released through the boat's macerator into the environment ?

No. There is nothing that can be added to a tank that will make it legal
to dump the tank inside the "3 mile limit." Nor does just passing through
a tank discharge macerator pump have time to macerate to the legal
standard. ONLY waste that is treated by a CG certified Type I or II MSD
and discharged directly overboard from the device is "treated waste."
It's not even legal to dump a tank full of waste that was treated by Type
I or II before it went into the tank...'cuz once it goes into a tank, it's
no longer considered "treated waste." Reason: the treatment device may
kill almost all the bacteria, but only one of the li'l buggers has to
survive to quickly multiply into zillions in the tank.

What say you, wise Peggy?

That you prob'ly oughta check out the link in my signature.

--
Peggie
----------
Peggie Hall
Specializing in marine sanitation since 1987
Author "Get Rid of Boat Odors - A Guide To Marine Sanitation Systems and
Other Sources of Aggravation and Odor"
http://shop.sailboatowners.com/boat_odors/