diff --git a/vlaplex.f90 b/vlaplex.f90
index 558957f..633924f 100644
--- a/vlaplex.f90
+++ b/vlaplex.f90
@@ -268,8 +268,9 @@ program VlaPlEx
     f_i_old(:,:,nv) = 0.0_dp
     sum_ni = 0.0_dp
     ! Advect in the r direction
-    !$omp parallel do
+    
     do iz = 1, nz
+      !$omp parallel do
       do i = 1, nr
         ! Advect negative velocity
         if (i < nr) then
@@ -296,9 +297,10 @@ program VlaPlEx
         end if
 
       end do
+      !$omp end parallel do
       sum_ni = sum_ni + Zave * n_i(iz,:)
     end do
-    !$omp end parallel do
+    
 
     ! Assume quasi-neutrality to start iterating
     n_e = 1.0_dp/nz * sum_ni