Embodiments are directed to an installation of a first tube made of a first material on a heat exchanger that is different from a second material associated with a second tube of the heat exchanger. The first tube is coupled to the second tube via a porous layer associated with the first tube. A signal is measured between the first tube and the second tube. The measured signal is logged as data. Information associated with a corrosiveness of an environment in which the heat exchanger is located is obtained based on the data.