i bought some more generic glyphosate, this one is called " pronto big ' n tuf nonselective agricultural herbicide" it' s made by gordons. 41% gly plus surfactants. in the booklet, it mentions that the addition of 1-2 percent of ammonium sulfate will increase the effectiveness of the mixture. no additional surfactant is necessary, because it is included. $35/gal, $85/2.5 gal.