diff --git a/bfps/_fluid_base.py b/bfps/_fluid_base.py
index edcb8723fafb42d5dbf7d2e0c7c6d852da0b0131..92aa5822498c90c026af8a4fc0a6fe0039edd283 100644
--- a/bfps/_fluid_base.py
+++ b/bfps/_fluid_base.py
@@ -206,6 +206,7 @@ class _fluid_particle_base(_code):
         self.main       += '}\n'
         self.main       += 'do_stats();\n'
         self.main       += 'do_particle_stats();\n'
+        self.main       += output_time_difference
         if self.particle_species > 0:
             self.main   += self.particle_end
         self.main       += self.fluid_end