List: trawlers@lists.trawlering.com
From: Scott H.E. Welch
Re: T&T: new holding tank installation
Tue, Feb 12, 2008 5:42 PM
David H Sorenson writes:
>If I recall, one major purpose of the vent is that when the holding tank
>is pumped out the vacuum pressure of the pumpout does not collapse the
>tank. Maybe you are talking about something else, but the pumpout
>stations around here make my holding tank moan and groan from the vacuum
>pressure being applied.
This is an excellent point. In fact, it's best to have not one but two vents,
at least 1" diameter, with the outlets on opposite sides of the vessel. This
will promote airflow through the tank and help with aerobic decomposition. By
the way don't make the mistake I did and install the vent hose with low
points. This will cause a buildup of water (from rain and or condensation)
and will have the same effect as a P-trap under a sink. The vent lines need
to be run in a continuous upward slope.
However, the "vented loop" will not help with this.
Scott Welch
FirstClass Product Manager
www.firstclass.com
Those who make no mistakes rarely make anything.