Drift reduction adjuvants want to increase droplet size but not increase surface tension. This usually means increasing the tensile strength of the water carrier of the spray solution. Almost all drift reduction agents work this way. The surface tension is not altered so your surfactant continues to work. However, the water carrier holds together longer as it exits the spray nozzle thus making a bigger drops. However, if the water holds together too tightly, when it does manage to break up into droplets, it breaks up into smaller, less controlable droplets, called “driftable fines”.
The above bell shaped curve shows the size of water droplets in microns as affected by the use rate of Drift-fiant on a spray volume basis. In other words there is an optimum rate, too little effect, no effect, too much effect meaning--the spray droplet will get small again. For most ground rigs that rate is about 24oz per 100 gallons of spray solution.