Empirical nucleation kinetics so called magma dependent power law model have been conventionally used for industrial crystallization. However, this type of nucleation kinetics can not explain instability of industrial crystallizers. In this paper, we reconsider nucleation kinetics as a function of first and second moments as well as magma density or third moment of population density. Cases-of second and third moments show a possibility of multiple steady states. Furthermore, using Hurwitz stability criterion we examine mechanisms of unstable steady state of crystallizers.