diff --git a/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml b/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
index 230c427cdb05..6e0153ead725 100644
--- a/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
+++ b/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
@@ -404,9 +404,9 @@ Default: Defined in namelist_defaults.xml
-Control what type of function is used for Redi $\kappa$.
+Control what type of function is used for Redi $\kappa$. For 'equalGM', RediKappa is set to gmBolusKappa, so picks up the closure used by GM. Note that equalGM should only be used with 2D GM schemes (e.g. config_GM_closure=constant or Visbeck), not with EdenGreatbatch.
-Valid values: 'constant', 'data'
+Valid values: 'constant', 'equalGM', 'data'
Default: Defined in namelist_defaults.xml
diff --git a/components/mpas-ocean/src/Registry.xml b/components/mpas-ocean/src/Registry.xml
index 150ad1dd3bb7..9e9128f39dda 100644
--- a/components/mpas-ocean/src/Registry.xml
+++ b/components/mpas-ocean/src/Registry.xml
@@ -295,8 +295,8 @@
possible_values=".true. or .false."
/>