diff --git a/components/mpas-ocean/bld/build-namelist b/components/mpas-ocean/bld/build-namelist
index 0b8d3c782fa7..238af2be2ab1 100755
--- a/components/mpas-ocean/bld/build-namelist
+++ b/components/mpas-ocean/bld/build-namelist
@@ -616,6 +616,8 @@ add_default($nl, 'config_use_cvmix');
 add_default($nl, 'config_cvmix_prandtl_number');
 add_default($nl, 'config_cvmix_background_scheme');
 add_default($nl, 'config_cvmix_background_diffusion');
+add_default($nl, 'config_cvmix_background_diffusion_passive_enable');
+add_default($nl, 'config_cvmix_background_diffusion_passive');
 add_default($nl, 'config_cvmix_background_viscosity');
 add_default($nl, 'config_cvmix_BryanLewis_bl1');
 add_default($nl, 'config_cvmix_BryanLewis_bl2');
diff --git a/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml b/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
index 4069eb144cff..d7e0485168c8 100644
--- a/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
+++ b/components/mpas-ocean/bld/namelist_files/namelist_defaults_mpaso.xml
@@ -229,6 +229,8 @@
 <config_cvmix_prandtl_number>1.0</config_cvmix_prandtl_number>
 <config_cvmix_background_scheme>'constant'</config_cvmix_background_scheme>
 <config_cvmix_background_diffusion>0.0</config_cvmix_background_diffusion>
+<config_cvmix_background_diffusion_passive_enable>.false.</config_cvmix_background_diffusion_passive_enable>
+<config_cvmix_background_diffusion_passive>0.0</config_cvmix_background_diffusion_passive>
 <config_cvmix_background_viscosity>1.0e-4</config_cvmix_background_viscosity>
 <config_cvmix_BryanLewis_bl1>8.0e-5</config_cvmix_BryanLewis_bl1>
 <config_cvmix_BryanLewis_bl2>1.05E-4</config_cvmix_BryanLewis_bl2>
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 01456cd6583a..6b1026ea4d11 100644
--- a/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
+++ b/components/mpas-ocean/bld/namelist_files/namelist_definition_mpaso.xml
@@ -747,6 +747,22 @@ Valid values: Any positive real value.
 Default: Defined in namelist_defaults.xml
 </entry>
 
+<entry id="config_cvmix_background_diffusion_passive_enable" type="logical"
+	category="cvmix" group="cvmix">
+Enable different background vertical diffusion value for passive tracer quantities
+
+Valid values: .true. or .false.
+Default: Defined in namelist_defaults.xml
+</entry>
+
+<entry id="config_cvmix_background_diffusion_passive" type="real"
+	category="cvmix" group="cvmix">
+Background vertical diffusion applied to passive tracer quantities if enabled
+
+Valid values: Any positive real value.
+Default: Defined in namelist_defaults.xml
+</entry>
+
 <entry id="config_cvmix_background_viscosity" type="real"
 	category="cvmix" group="cvmix">
 Background vertical viscosity applied to horizontal velocity
diff --git a/components/mpas-ocean/src/Registry.xml b/components/mpas-ocean/src/Registry.xml
index f8b56c083d44..5524651cc185 100644
--- a/components/mpas-ocean/src/Registry.xml
+++ b/components/mpas-ocean/src/Registry.xml
@@ -477,6 +477,14 @@
 					description="Background vertical diffusion applied to tracer quantities"
 					possible_values="Any positive real value."
 		/>
+		<nml_option name="config_cvmix_background_diffusion_passive" type="real" default_value="1.0e-5" units="m^2 s^-1"
+					description="Background vertical diffusion applied to passive tracer quantities"
+					possible_values="Any positive real value."
+		/>
+		<nml_option name="config_cvmix_background_diffusion_passive_enable" type="logical" default_value=".false."
+					description="flag to enable using a different background vertical diffusion for passive tracers"
+					possible_values=".true. or .false."
+					/>
 		<nml_option name="config_cvmix_background_viscosity" type="real" default_value="1.0e-4" units="m^2 s^-1"
 					description="Background vertical viscosity applied to horizontal velocity"
 					possible_values="Any positive real value."
@@ -3085,6 +3093,10 @@
 			 description="vertical diffusion defined at the cell center (horizontally) and top (vertically)"
 			 packages="forwardMode;analysisMode"
 		/>
+		<var name="vertDiffPassiveTopOfCell" type="real" dimensions="nVertLevelsP1 nCells Time" units="m^2 s^-1"
+			 description="vertical diffusion defined at the cell center (horizontally) and top (vertically) for passive tracers"
+			 packages="forwardMode;analysisMode"
+		/>
 		<var name="bulkRichardsonNumber" type="real" dimensions="nVertLevels nCells Time" units="1"
 			 description="CVMix/KPP: bulk Richardson number"
 			 missing_value="FILLVAL" missing_value_mask="cellMask"
diff --git a/components/mpas-ocean/src/shared/mpas_ocn_diagnostics_variables.F b/components/mpas-ocean/src/shared/mpas_ocn_diagnostics_variables.F
index 567c3efc183c..b64890a25691 100644
--- a/components/mpas-ocean/src/shared/mpas_ocn_diagnostics_variables.F
+++ b/components/mpas-ocean/src/shared/mpas_ocn_diagnostics_variables.F
@@ -141,6 +141,7 @@ module ocn_diagnostics_variables
    type (field2DReal), pointer :: wettingVelocityField
 
    real (kind=RKIND), dimension(:,:), pointer :: vertDiffTopOfCell
+   real (kind=RKIND), dimension(:,:), pointer :: vertDiffPassiveTopOfCell
    real (kind=RKIND), dimension(:,:,:), pointer :: vertNonLocalFlux
    integer, dimension(:,:), pointer :: rediLimiterCount
    real (kind=RKIND), dimension(:,:,:), pointer :: activeTracerSurfaceFluxTendency
@@ -494,6 +495,8 @@ subroutine ocn_diagnostics_variables_init(domain, jenkinsOn, hollandJenkinsOn, e
                    vertViscTopOfCell)
          call mpas_pool_get_array(diagnosticsPool, 'vertDiffTopOfCell', &
                    vertDiffTopOfCell)
+         call mpas_pool_get_array(diagnosticsPool, 'vertDiffPassiveTopOfCell', &
+                   vertDiffPassiveTopOfCell)
          call mpas_pool_get_array(diagnosticsPool, 'vertAleTransportTop', &
                    vertAleTransportTop)
          call mpas_pool_get_array(diagnosticsPool, 'vertTransportVelocityTop', &
@@ -752,6 +755,7 @@ subroutine ocn_diagnostics_variables_init(domain, jenkinsOn, hollandJenkinsOn, e
          !$acc                   barotropicForcing,               &
          !$acc                   vertViscTopOfCell,               &
          !$acc                   vertDiffTopOfCell,               &
+         !$acc                   vertDiffPassiveTopOfCell,        &
          !$acc                   GMStreamFuncZonal,               &
          !$acc                   relativeVorticity,               &
          !$acc                   kineticEnergyCell,               &
@@ -999,6 +1003,7 @@ subroutine ocn_diagnostics_variables_destroy(err) !{{{
          !$acc                   barotropicForcing,               &
          !$acc                   vertViscTopOfCell,               &
          !$acc                   vertDiffTopOfCell,               &
+         !$acc                   vertDiffPassiveTopOfCell,        &
          !$acc                   GMStreamFuncZonal,               &
          !$acc                   relativeVorticity,               &
          !$acc                   kineticEnergyCell,               &
@@ -1204,6 +1209,7 @@ subroutine ocn_diagnostics_variables_destroy(err) !{{{
                  barotropicForcing,               &
                  vertViscTopOfCell,               &
                  vertDiffTopOfCell,               &
+                 vertDiffPassiveTopOfCell,        &
                  GMStreamFuncZonal,               &
                  relativeVorticity,               &
                  kineticEnergyCell,               &
diff --git a/components/mpas-ocean/src/shared/mpas_ocn_vmix.F b/components/mpas-ocean/src/shared/mpas_ocn_vmix.F
index 87f23d65aa1f..4c96c6e952dc 100644
--- a/components/mpas-ocean/src/shared/mpas_ocn_vmix.F
+++ b/components/mpas-ocean/src/shared/mpas_ocn_vmix.F
@@ -1583,9 +1583,26 @@ subroutine ocn_vmix_implicit(dt, meshPool, statePool, forcingPool, scratchPool,
                !$acc enter data copyin(tracerGroupSurfaceFlux)
 #endif
 
-               call ocn_tracer_vmix_tend_implicit(dt, vertDiffTopOfCell, layerThickness, tracersGroup, &
+               if (trim(groupItr % memberName) /= 'activeTracers' .and. &
+                   config_cvmix_background_diffusion_passive_enable) then
+                      vertDiffPassiveTopOfCell = vertDiffTopOfCell - &
+                         config_cvmix_background_diffusion + config_cvmix_background_diffusion_passive
+#ifdef MPAS_OPENACC
+                      !$acc update host (vertDiffPassiveTopOfCell)
+#endif
+!maltrud debug
+ do k = 1, maxLevelCell(1)
+  write(*,*)' DEBUG01: ',k,vertDiffPassiveTopOfCell(k,1)
+ enddo
+
+                      call ocn_tracer_vmix_tend_implicit(dt, vertDiffPassiveTopOfCell, layerThickness, tracersGroup, &
+                        vertNonLocalFlux, tracerGroupSurfaceFlux,  &
+                        config_cvmix_kpp_nonlocal_with_implicit_mix, err)
+               else
+                      call ocn_tracer_vmix_tend_implicit(dt, vertDiffTopOfCell, layerThickness, tracersGroup, &
                         vertNonLocalFlux, tracerGroupSurfaceFlux,  &
                         config_cvmix_kpp_nonlocal_with_implicit_mix, err)
+               end if
 #ifdef MPAS_OPENACC
                !$acc exit data delete(tracerGroupSurfaceFlux)
 #endif