diff --git a/cmake/BuildParFlow.cmake b/cmake/BuildParFlow.cmake
index 708e14a..d3f9f65 100644
--- a/cmake/BuildParFlow.cmake
+++ b/cmake/BuildParFlow.cmake
@@ -77,8 +77,8 @@ ExternalProject_Add(ParFlow
                 -DPARFLOW_AMPS_SEQUENTIAL_IO=ON
                 -DPARFLOW_ENABLE_TIMING=TRUE
                 -DPARFLOW_ACCELERATOR_BACKEND=${PF_ACC_BACKEND}
-                -DMPIEXEC_EXECUTABLE=${MPIEXEC_EXECUTABLE}
-                -DMPIEXEC_NUMPROC_FLAG=${MPIEXEC_NUMPROC_FLAG}
+                -DMPIEXEC_EXECUTABLE=${SLURM_SRUN}
+                -DMPIEXEC_NUMPROC_FLAG=--ntasks
                 -DPARFLOW_ENABLE_SLURM=${ENABLE_SLURM}
                 ${PF_CLM_FLAGS}
     DEPENDS     ${MODEL_DEPENDENCIES}