Hello All - I use COMSOL in the context of groundwater (Earth Sciences Module). I have run across a problem where I am representing, instead of a point source of pollution, a quadralateral geometry (2D) pollutant source (constant concentration source). COMSOL is constantly computing negative concentrations (which become more negative with time) in my flow field as a solution. Has anyone run across this problem before? I searched and found this issue as a common problem under COMSOL's website but I do not have a license key (I use COMSOL on a public terminal) to read the response. Thanks.