I have a small field sprayer , 300 gal 27 ft. booms, that I have used since the late 70's. When I drill beans I leave the wheel run on the other wheel mark going one way to help get a guide when I spray and crops in rows is easy. But this year I sprayed some no till beans that I didn't plant and I lost my way is several places. You can't see where to go if you can't see where you been, so I'm thinking of building a foam marker to just drop foam in the center. Question is how big a pipe to run the foam and how big a foam tank to mark 15 ac. ......