1 qt of the marking dye will give a nice color for about a 100 gallons of spray. I mix 2 qts for my 200 gal sprayer. This time of year, you may have better luck with red dye. Green is tough to see. I generally use blue and pay about $80 for a 2 1/2 gal jug which cover about 30 acres. It is fairly expensive, but if your overlapping too much or not overlapping at all, you are wasting money on your herbicides.