okay, we're going in to fertilizing and weed control next season. we plan to do granular applications. so if we are going to spray trees and bushes, how large of tank sprayer do i really need? can i just get a small portable tank, or do i need a 200 or 300 gal unit. we do have a few larger commercial properties and a lot of residential. but really have no idea how big we will get this year.