[en] The structure and magnetic interactions of the triplon Bose–Einstein condensation candidates Ba₃Cr₂O₈ and Sr₃Cr₂O₈ have been studied thoroughly in the literature, but little is known about a possible triplon condensation in the corresponding solid solution ${\mathrm{B}\mathrm{a}}_{3-<!--\; ???\; -->x}$Sr_xCr₂O₈. We have prepared various members of this solid solution and systematically examined their magnetic properties in high magnetic fields up to $60\mathrm{T}$ and at low temperatures down to $340\mathrm{m}\mathrm{K}$, by means of pulsed field and cantilever magnetometry. From these experiments for $x\in <!--\; ???\; -->\{3,2.9,2.8,2.7,2.6,2.5\}$, we find that the critical fields of ${\mathrm{B}\mathrm{a}}_{3-<!--\; ???\; -->x}$Sr_xCr₂O₈ decrease monotonically with decreasing Sr content x. This change is in good agreement with the earlier reported variation of the magnetic interactions in these compounds. (paper)