I just replaced my holding tank and lines and am wrestling with the same issue. The vent on my tank is 5/8 inch hose that goes up to one of those little silver vents on the topsides just below the hull/deck joint. No way that allows the air to flow correctly in a 5/8 inch hose. What I plan to do is replace that vent fitting with a regular thru-hull so that the maximum amount of air can move freely in and out.
SailorMitchSailing winged keels since 1989.
1.20.09 Bush's last day the end of an error !! Hopefully we still have a constitution and economy left by then.
"Compassion and tolerance are not a sign of weakness, but a sign of strength." The Dalai Lama
good planets are hard to find-- a song by steve forbert
I have but one lamp by which my feet are guided, and that is the lamp of experience. I know no way of judging the future but by the past.-- Patrick Henry.