Provided is a coreflood apparatus that comprises a housing, an inlet, an outlet, and two chambers positioned within the housing that are configured to retain porous media. The apparatus includes a partition coupled to an inner surface of the housing between the two chambers and a sensor mounting location. Provided is a method of introducing a fluid into the coreflood apparatus and allowing fluid to pass through chambers in the apparatus having a sensor mounting location there between. Further provided is a coreflood system comprising a coreflood apparatus, a calcium ion sensor, and a data processing device. Provided is a method of introducing fluid into the coreflood system and allowing fluid to pass through chambers in the system having a calcium ion sensor there between. The method further comprises detecting calcium ions in the fluid and determining calcium ion concentration data.