This study will examine a process of slow dynamic change in surface excess of a unique pH-responsive chelating surfactant at the air/liquid interface that occurs over a period of hours. Our earlier, preliminary studies of this phenomenon are focused on equilibrium conditions and to our knowledge, such slow equilibration processes has never been reported for surfactant systems before and the proposed study is therefore of fundamental importance. The specific surfactant is also of direct interest in cleaning contamination of heavy metals and mineral processing. Studying dynamics at the air/water interface is challenging and we need fast measurements: the INTER reflectometer is best suited for these experiments. The thickness of the surfactant layers also provides understanding of the changes at the air/liquid interface and that information is uniquely determined by reflection measurements.