Is this statement true? &
"If the label of a disinfectant says to use a dilution of 1 standard US measuring cup per gallon of water, using 2 cups/gallon will be twice as effective"
the statement is false. Nominal dilution of a disinfectant& kills 90-99% of all microbes (depending on disinfectant). If you make a smaller dilution of disinfectant, it will kill more microbes, but the difference will be insignificant. For example, if usual dilution of disinfectant (1 cup per gallon) kills 95% of microbes, a smaller dilution (2 cup per gallon) will kill 99% of microbes, so efffectiveness in this case will be 4% more in comparison with normal dilution.