How to install holding tank ventilation with Wema HFL 70? (Done in a 1982 Nauticat 38)

Holding tanks need a good ventilation in order to perform well. With more ventilation you will get less bad smell. When you want to empty your holding tank by sucking out the sh!t, you need a good ventilation, if not your tank can be damaged by the negative air preassure.
So, how to install a good ventilation in your holding tank?
In this video you can see how we make a hole in the tank. Then we install a Wema flange on which we mound a hose connection and a hose.
Here are some of the parts we use:
seatronic.no/monteringsflens-...
seatronic.no/trudesign-90-gra...
www.maritim.no/slange-stalarm...
www.frigus.se/
www.westsystem.no/produkt/mon...