Commercial applicator told us how to do that............and then after looking at the pump we had bot, we realized how simple it was.

The unload hose has a shutoff valve 10ft from its end..............by activating a mechanism on the pump (I don't understand how it works----has something to do with creating a vaccuum in the hose, I think) and letting that pump for a few seconds, that empties the hose pretty much......not a 100%, but if the valve in the hose is shut off, that leaves the last 10ft empty.

I don't think there is anything magic about the 10ft........but I think there is with respect to style, brand, height etc etc of the pump for the load stands.

So..........don't really have a problem with too much mess and hooking/unhooking at the fields-----that couldn't be overcome with a little pre-thought.

At the confinements, with the pit pump.............different story.  Not sure about how that pump works.........I assume it sucks back, although I cannot say I have seen it done yet.........haven't had to..........load stand height has taken care of any runback.

And, I don't see why we couldn't set up a little elevation between pit pump and end of fill hose.......and put a valve in that.............so the end of that hose ought to be empty also........but if we had rock there, let it run into the rock.