diff --git a/t3/main.py b/t3/main.py
index db3e8d94..a750a7fc 100755
--- a/t3/main.py
+++ b/t3/main.py
@@ -707,7 +707,8 @@ def determine_species_to_calculate(self) -> bool:
         if self.t3['options']['all_core_species']:
             for species in self.rmg_species:
                 if self.species_requires_refinement(species=species):
-                    species_keys.append(self.add_species(species=species, reasons=['All core species']))
+                    species_keys.append(self.add_species(species=species,
+                                                         reasons=[f'(i {self.iteration}) All core species']))
         else:
             # 1. SA observables
             sa_observables_exist = False