We wish to extend previous studies on the adsorption of binary surfactant systems at the air water interface by the addition of NaCl and CaCl2: mimicking the 'hard water' environment. The focus will be on looking at the change in adsorption as the temperature is dropped from 25oC to 10oC as these low temperature systems are poorly understood; previous experiments show a very significant change in adsorption of certain non ionic/anionic mixtures, which this proposal hopes to further understand. The addition of these electrolytes and their effects on the proposed surfactants have been extensively studied at 25oC, typically showing a decrease in the area per molecule and increased surface activity.