Bruce Richards wrote:
I am looking for advise on the pros and cons of locating the waste
holding tank at an elevation slightly above the toilet (aproximately
16") verses the same or lower elevation. A higher elevation would
enable gravity flow to empty the holding tank in legal waters but I am
concerned about any problems it may create in toilet function or other
unforeseen issues. I would rather ask than create a stink!

I wouldn't call 16" a "slight" elevation above the toilet...that puts
the bottom of the tank above the top of the bowl. I wouldn't do
it...'cuz that's likely to leave waste and/or flush water in the head
discharge hose to run back down into the bowl...how much depends on how
long the head discharge hose is.

I suggest you find a location within 6' of the toilet that will put the
tank close the same level as the toilet. It's ok if the bottom of the
tank is a few inches above the base of the toilet, 'cuz you should have
a loop in the head head discharge line immediately after the toilet
that's above the top of the tank anyway--to prevent heeling from sending
waste in the tank back into the bowl.

You're not limited to the few rectangular tanks shown in the marine
catalogs, btw...Ronco Plastics makes even better quality tanks for a
very reasonable price, and have more than 400 shapes and sizes to choose
from--including over 100 that are non-rectangular to fit just about any
space on a boat. And they install fittings in the sizes and locations
specified by the customer when they make the tank. Their catalog is on
their website at http://www.ronco-plastics.com (I don't have any
connection with 'em, btw...they supplied at least 90% of the tanks we
sold when I still owned my company.)

If you'd like some help in spec'ing out a system you'll be happy with
(or as happy as it's possible to be with a holding tank--at least
trouble-free and odor-free, anyway), I'll be glad to help you.
--
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://shop.sailboatowners.com/detai...=400&group=327

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