diff --git a/regression_tests/tests/prom/mixed_nonlinear_diffusion.sh b/regression_tests/tests/prom/mixed_nonlinear_diffusion.sh
index bf8af6063..d1a01f4a5 100755
--- a/regression_tests/tests/prom/mixed_nonlinear_diffusion.sh
+++ b/regression_tests/tests/prom/mixed_nonlinear_diffusion.sh
@@ -3,8 +3,8 @@ source $GITHUB_WORKSPACE/regression_tests/common.sh
 CMDS=( 
     "./mixed_nonlinear_diffusion -offline -tf 0.01"
     "./mixed_nonlinear_diffusion -merge -ns 1 -tf 0.01"
-    "./mixed_nonlinear_diffusion -online -tf 0.01 -rrdim 2 -rwdim 2 -nldim 3"
-    "./mixed_nonlinear_diffusion -online -tf 0.01 -rrdim 2 -rwdim 2 -nldim 3 -sopt"
+    "./mixed_nonlinear_diffusion -online -tf 0.01 -rrdim 2 -rwdim 2 -nldim 3 -hrtype deim"
+    "./mixed_nonlinear_diffusion -online -tf 0.01 -rrdim 2 -rwdim 2 -nldim 3 -hrtype sopt"
     "./mixed_nonlinear_diffusion -online -tf 0.01 -rrdim 2 -rwdim 2 -nldim 3 -ns 1 -eqp -maxnnls 4"
 )
 TYPE="PROM"