What might need to happen to herbicide dosage in very hard water?

In very hard water, the presence of high levels of calcium and magnesium can significantly affect the efficacy of certain herbicides. These minerals can form complexes with the active ingredients in the herbicide, rendering them less effective at controlling target aquatic plants. As a result, to achieve the desired herbicidal effect, it may be necessary to increase the herbicide dosage. Doubling the dosage in very hard water helps to compensate for the reduced availability of the active ingredient due to these interactions, ensuring that enough of the herbicide remains effective at the target site. This adjustment is crucial for maintaining effective pest control in challenging water conditions.