[Public-List] Holding tanks

[Don Lang]

I attended a marine sanitation seminar this winter; here is a few things I learned:

Any type of flexible hose that contains standing sewage will be permeated by the sewage and cause odors.
Therefore whenever possible use schedule 40 PVC (not ABS its too brittle) and not flexible hose, and always use PVC
for all lines that will hold standing sewage. Keep flexible hose runs as short as possible.
Use PVC hose barbs for tanks fittings and not maralon, nylon etc. as they will also be permeated over time.
When using flexible sanitation hose you may warm the end gently with a heat gun to make it easier to connect, never use soaps or oils, etc.
When comparing sanitation hoses (apples to apples) the less flexible the hose, the longer it will take to become permeated and cause odors.
They said the more flexible the hose, the further apart the molecules that make it up are; fewer molecules = more easily permeated.
Not sure if the hose is causing the odor you smell; wipe it with a clean cloth and take the cloth outside into fresh air, if the hose is permeated the cloth will smell.
If you use a holding tank filter on the vent line ensure that you change it out if it becomes wet and there is no low spots in the line that can restrict the vent.
Dock-side suction pumps can pull over 30 psi and a restriction in the vent line (or undersized vent)   causes many tank and fitting failures  and can fatigue tanks and fittings even it it does not cause them to fail at that particular instance.

Cheers, Don (#473)





George,
I  took delivery this week of a 14 gal holding tank (14D20814) to install in
Ginseng, Hull # 574, ordered from Raritan Engineering Inc.
I read the Raritan holding tank installation article you posted on the
Alberg 30 site and was wondering in hind sight if there was anything you
would do differently now that you have had it installed for a number of
seasons?
Peter Milley







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