Elliott Alterman wrote:
After 2+ years of no problems, in the Bahamas and the U.S., the head vent on
our sailboat has become a problem in the last year. We try to do the right
thing: Odorlos, regular pumpouts with fresh water, etc. We are thinking
about installing an inline filter for the vent, thinking about using
something called the Shock treatment, etc.
But, before we do those things, we are looking for other suggestions.
I've never heard any product called "shock treatment"...I suspect it's
just what people call flushing out the tank with a heavy dose of bleach
in the mistaken belief that'll cure an odor problem (it won't).
And I'm not a fan of vent filters at all, but really don't like 'em on
sailboats. They're expensive--$50+--only last a year at most, and are
"toast" immediately if they ever get wet...which is just about
impossible to prevent on any sailboat that spills waste out the vent
when they're heeled, and also makes it impossible to flush out the vent
line to prevent those spills from clogging up the vent.
If everything was fine for more than 2 years, then suddenly "went
south," it has to mean that something in the system has changed that
affects the amount of oxygen in the tank. And that can ONLY be the vent.
So let's figure out what...
Have you been using a chemical tank product, only switching to Odorlos
AFTER you began to experience odor out the vent? If so, are you trying
to combine Odorlos with anything else?
Have you changed the vent...rerouted it to different thru-hull and/or
made it longer with additional bends in it?
When if ever have you checked your tank vent for a blockage or partial
blockage? The two most likely places are the thru-hull and the
connection on the tank. If you're outside of coastal US waters most of
the time, you prob'ly haven't been using the tank much...and that
creates a perfect opportunity for the vent to clog up. Any waste that's
spilled out while heeled when you were using has a chance to harden and
build up in the thru-hull and tank fitting...insects, even dust and
pollen, can build up in the thru-hull...and either or both can block it
partially or completely.
In most cases, a total blockage would pressurize the tank, creating
increasing backpressure when you flush the toilet. But if you're only
using the tank intermittently when you have to, enough air could escape
back through the toilet to keep the tank from pressurizing. And if
there's not much in the tank when you pump it out or dump it, there
could still be enough air in the tank to allow it to be emptied before
the pumpout or macerator pulls a vacuum. A partial blockage wouldn't
necessarily cause any problems BUT an increase in odor out the vent.
If there's much of a bend in the vent line, it may have collapsed and
kinked.
Any of the above is possible...the one thing I'm sure of is that the
problem IS the tank vent--that something about it has changed that's
reducing the air flow. Find it and you'll cure the odor problem.
--
Peggie
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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://69.20.93.241/store/customer/p...40&cat=&page=1