Single use pouches of prepared Singlet Standard Solutions from Hach Co., of Loveland, Colo., are ideal for pH and conductivity measurements anywhere. Users simply tear open the foil pouch, insert an electrode and complete meter calibration. Using Singlet Solutions eliminates standard contamination during on-site testing and the need for transporting deionized or demineralized water for standards preparation. Singlet Standard Solutions are available for pH 4, 7 and 10 buffer values.