Peggie,
Question have you ever heard of or used forded mechanical aeration of marine
holding tanks?
Two options come to mind 1.) install a 10 VDC computer chip cooling fan in a
tank vent line where the tank has two vents. for example a 5.3 CFM (free
air) fan draws 1.08 watts power (at 24/7 operation this is about 2.2 AH
draw) and is about 1-1/2" diameter which can be adapted to fit in-line in
one of the vent hoses. 2.) better solution a battery powered AQUARIUM AIR
PUMP available on the shelf at PETCO for $13.00. It comes with its own air
release stone that would be dropped into the holding tank and feed through a
3/8? O.D. plastic hose that is run-through the wall of one vent line. the
air pump is quite and aerates the stored liquid much as a commercial
wastewater sewage treatment facility not just the surface layer like tank
vents. The air pump is designed to hold two C-size batteries with an
estimated 2-week life or about 1.3 AH on a 24/7 operation schedule. KISS
would be to replace the "Dry-Cells" every two weeks, but if someone wanted
to get really fancy with this installation they could install rechargeable
C-Cells and hook them into either a solar panel (al-a NICRO-VENT or into the
12 VDC "House" battery through a dropping resister to get the 3 VDC at the
air pump.
I realize that these options add another level of complication to the marine
head equation but it does away with all odor problems without the cost of
additional of chemicals.
What is your opinion on either of these mechanical aeration schemes.
Jim Maxey ME

"Peggie Hall" wrote in message
...
Peggie, I have a question, kinda related to this thread. I think I've
read/understood that a well "aired" holding tank is the best way
to reduce oders.

Yep...oxygen is the key to odor elimination.

So, being an engineer, I'm wondering if a two
hose holding tank vent arrangement...one "inlet" and one "outlet",
might work.
The forward hose leads to the bow, the aft hose leads to the
stern.

It would actually work better if both lines went forward...'cuz that
would mean air would be forced into the tank no matter which tack you're
on. Nor does it require two vent lines if the vent line is short enough
( 5') and has a 1" ID...'cuz air forced in has no trouble pushing
gasses in the tank out the same line.

The theory is that there would be constant airflow into,
(and out of) the holding tank. assuming the vents at each end
encouraged such flow.

A line leading aft that's too long wouldn't be under enoug pressure to
get the job done without an inline exhaust fan to help it. You'd
actually be better off with a single 1" short vent.


Is this a stupid idea?

Noooo...not stupid at all! It only proves you're thinking in the right
direction. I'd have to see a diagragm of your installation before I
could tell you what you need to do to make it work.

--
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://www.seaworthy.com/html/get_ri...oat_odors.html