It makes no difference how much water you mix it with. The water does nothing and is just a carrier. The important thing is to use the correct amount of Cutrine for the area you are treating. I don't like mixing it strong because it is easy for me to run out of the spray mix before I cover the desired area. I mix 1/2 gal of Cutrine with 10 gallons of water and try to disperse it evenly over half my pond from by luxury pontoon boat. That beauty is a massive 6ft. by 8ft all aluminum flat deck propelled by a water churning 35 pound thrust trolling motor I bought as is at a yard sale for 2 bucks.