Fill with resin to the neck of the vessel.
Is that how everyone does it?
I just started using a DI only set up and filled two 11 L blue pressure vessels up with Dowex resin.
The screw tops of the vessels have a long filter attached underneath. If you fill the vessel up to the neck how would you get the filters in?
I filled them until they were
three quarters full with resin (using a scoop) and then whilst shaking the vessel, pushed the filters down until I was able to close the top.
I know there is still space because I can hear the resin move if I shake it.