diff --git a/flash2d/src/options-sphere/SLM_simple_stacked.f90 b/flash2d/src/options-sphere/SLM_simple_stacked.f90
index 16b1ee921d5cfbdd956f4c902c3c5d450076741f..6b9ce240032448f213cf3ef360e8c437259e8595 100644
--- a/flash2d/src/options-sphere/SLM_simple_stacked.f90
+++ b/flash2d/src/options-sphere/SLM_simple_stacked.f90
@@ -197,7 +197,7 @@
 
 !-SLM--------- put alpha values to u and v field entries
 
-      i_start= i_stcuv+ i_layerid-2
+      i_start= (i_stcuv-1)+ GRID_dimension*(i_layerid-1)
       i_uvpointer = (/ ((i_start+i_cnt), i_cnt=1,GRID_dimension) /)
       r_alpha= -r_alpha
       IF(present(i_newsdepth)) THEN