This study concerns double diffusive convection. Of interest is the extension of current modeling capabilities of "diffusive" type fluid interface. A unique feature of the model to be developed is that it will be capable of predicting both interface erosion and growth. A series of experiments will be performed in conjunction with the development of theoretical model. A numerical model will be developed for long-term simulation of a diffusive interface. Diffusive interface research is basic research that can have direct impacts within the chemical and material processing areas. Within the chemical processing area, potentially disastrous effects can occur when a diffusive interface exists within a containment vessel. The interface can control reaction or vaporization rates. If the interface erodes, these rates can increase to uncontrollable levels. An example of this situation is the LNG rollover phenomena.