I'm throwing ideas around in my head about putting two 500 gallon spray tanks on an old miller pro pull behind sprayer. One tank to apply roundup or status, or what have you, and the other flowing to drop nozzles to apply N. Running off of seperate pumps, with a valve between the 2 so it could be used as a 1000 gallon sprayer if I wanted to. If I have a piece of corn where something goes wrong and it needs some herbicide, seems like a great time to dribble some N on if it calls for it. No need to waste a trip, right? Anyone else thought of this, or has anyone built one?