diff --git a/tutorials/cfdemSolverRhoPimpleChem/Particle_in_Duct/DEM/in.liggghts_run b/tutorials/cfdemSolverRhoPimpleChem/Particle_in_Duct/DEM/in.liggghts_run
index e5a37e70..19aa7891 100644
--- a/tutorials/cfdemSolverRhoPimpleChem/Particle_in_Duct/DEM/in.liggghts_run
+++ b/tutorials/cfdemSolverRhoPimpleChem/Particle_in_Duct/DEM/in.liggghts_run
@@ -50,7 +50,7 @@ fix     cfd2 all couple/cfd/force
 fix     cfd3 all couple/cfd/chemistry n_species 2 species_names O2 CO2
 
 # this should shrink the particle
-fix     cfd4 all chem/shrink speciesA O2 molMassA 31.99 speciesC CO2 molMassC 44.01 molMassB 12.01 k 2.5e3
+fix     cfd4 all chem/shrink speciesA O2 molMassA 31.99 speciesC CO2 molMassC 44.01 molMassB 12.01 k 2.5e3 rmin 0.02
 
 # apply nve integration to all particles that are inserted as single particles
 fix     integr all nve/sphere