The paper is devoted to the investigation of the linear stability of homogeneous pulsating vertical seepage of mixture through horizontal porous layer with solute immobilization. The mixture flow through porous medium is studied within the standard Darcy-Boussinesq approach taking into account the solutal convection. The immobilization of solute particles by solid matrix of medium is described by the mobile/immobile media (MIM) model with second-order kinetics. It was shown earlier that the immobilization leads to oscillatory mode of convective instability due to transition of solute from the mobile phase to immobile one. This means that immobilization effect on the flow pulsations should be non-trivial. The equations for the convection with immobilization are derived, the regime of homogeneous filtration is obtained and its stability is investigated. The neutral curves in the parameter space are plotted. The effect of homogeneous filtration stabilization under intensification of external seepage and dynamics inter phase exchange is studied. It is found that the effect of pulsations is significant in the case when frequency of pulsations is close to the natural frequency of instability. The parametric excitation of convection is not observed. (C) 2018 Elsevier Ltd. All rights reserved.