Plumbing vents

[Papabear]

Ok, With my vest to "geterdone" and my OCD, I have jumped ahead of myself. I have the wall in and done on my shower/kitchen side of the bus. Gray water tank to sit under the shower, black water on the opposite side of the frame. I did not run a vent up through the shower wall to vent the grey water. My question to the plumbing gurus. Can I tie into the black water vent by just running a vent line (above ftrame/under body) and have it still vent correctly? That would give me an abrupt 90 degree turn coming off my gray tank.
I don't want tear my finished wall and cabinet out.

[Seeria]

For the plumbing challenged like me How high does a black or gray water tank have to be? Can't you just put a tiny vent on the tank itself rather than running pipes to the roof?

[GoneCamping]

You will also have the tank venting fumes under your bus, and possibly rising in through what ever cracks it can find. I ran mine up through the floor, inside a wall and through the roof and put standard caps on them. In retrospect I could have tied the vent together and run one of them up, but I did 2 of them. There is a reason they put them on the roof of your house!

[Sojakai]

Here are two sites that both talk about those vents...

http://rvnow.rvtravel.com/2008/02/rv...with-wind.html

But for this one, I am pretty sure that you could also use one of the solar vents instead and then not have to worry about powering it. But then it would be on whenever the sun is shining.
http://www.modmyrv.com/2008/10/02/rv...dor-controller