Did an MRI on a lady who "sales/distributes" this stuff to golf courses and sech, she says mixing it any stronger than labeled is wasting it, as it is formulated to work at specific percentages,,follow the label. My buddy who is the maintenance super at a golf course, he use to mange 6 of 'em, confirmed what she had to say. Hell, they spray it on grain crops, that we eventually consume, and it is some nasty stuff,,hard to believe the "enviro-whackos/police" worry about a homeowner mixxing it a little strong. I give my 2 gal. sprayer a shot and spray the hell outta' anything I can't reach with my mower, never measure the dose, and it works quite effectively, it's a surfactant and non-residual,, my weed whacker is like brand new..