diff --git a/examples/global-lunar-bombardment/ctem.in b/examples/global-lunar-bombardment/ctem.in
index 6c924f20..14f15369 100644
--- a/examples/global-lunar-bombardment/ctem.in
+++ b/examples/global-lunar-bombardment/ctem.in
@@ -11,12 +11,12 @@ testyoffset  0.0                            ! y-axis offset of crater center fro
 tallyonly    F                                 ! Tally the craters without generating any craters
 testtally    F   
 quasimc      T                                 ! MC run constrained by non-MC 'real' craters given in a list
-realcraterlist    qmctest.in                ! list of 'real' craters for Quasi-MC runs
+realcraterlist    craterlist.in                ! list of 'real' craters for Quasi-MC runs
 
 
 
 ! IDL driver in uts
-interval     0.1
+interval     628.0
 numintervals 1                                  ! Total number of intervals (total time = interval * numintervals) <--when runtype is 'single'
 restart      F                                  ! Restart a previous run
 impfile      NPFextrap.dat          ! Impactor SFD rate file (col 1: Dimp (m), col 2: ! impactors > D (m**(-2) y**(-1))
@@ -34,9 +34,9 @@ runtype      single                             ! Run type: options are normal /
 
 ! CTEM required inputs
 seed         76535                    ! Random number generator seed
-gridsize     2000                          ! Size of grid in pixels
+gridsize     500                          ! Size of grid in pixels
 numlayers    10                                 ! Number of perched layers
-pix          3.08e3                           ! Pixel size (m)
+pix          12.32e3                           ! Pixel size (m)
 mat          rock                               ! Material (rock or ice)
 ! Bedrock scaling parameters
 mu_b         0.55e0                             ! Experimentally derived parameter for bedrock crater scaling law 
@@ -69,8 +69,10 @@ doangle         T                               ! Vary the impact angle. Set to
 Kd1             0.0001
 psi             2.000
 fe              4.00
-ejecta_truncation 4.0
+ejecta_truncation 24.0
 doregotrack T
-dorays  F 
+dorays  T 
 superdomain F
 dorealistic F
+domixing T
+dotopodiffusion F
\ No newline at end of file
diff --git a/src/crater/crater_populate.f90 b/src/crater/crater_populate.f90
index af208249..5d031596 100644
--- a/src/crater/crater_populate.f90
+++ b/src/crater/crater_populate.f90
@@ -333,7 +333,9 @@ subroutine crater_populate(user,surf,crater,domain,prod,production_list,vdist,nt
             call io_updatePbar(message)
             craters_since_subpixel = icrater - icrater_last_subpixel
             finterval = craters_since_subpixel / real(ntotcrat,kind=DP)
-            !call crater_subpixel_diffusion(user,surf,nflux,domain,finterval,kdiff)
+            if (user%dotopodiffusion) then
+               call crater_subpixel_diffusion(user,surf,nflux,domain,finterval,kdiff)
+            end if
 
                ! Do superdomain ray deposits
                ! Do sub-pixel craters vertical mixing
diff --git a/src/globals/module_globals.f90 b/src/globals/module_globals.f90
index 6dd487ea..5d5ddfa6 100644
--- a/src/globals/module_globals.f90
+++ b/src/globals/module_globals.f90
@@ -234,6 +234,8 @@ module module_globals
    logical           :: doscour  ! Set T to use the ejecta scouring model (EXPERIMENTAL)
    ! Crustal thinning variables
    logical           :: docrustal_thinning ! Set T to use the crustal thinning model (EXPERIMENTAL)
+   ! Diffusion variables
+   logical           :: dotopodiffusion ! set T to do subpixel diffusion; default T; should be F for melt distribution runs
 
    logical           :: killatmaxcrater ! Set T to end the run when a crater exceeds the maximum allowable size
    
diff --git a/src/io/io_input.f90 b/src/io/io_input.f90
index 30d155e2..b89b2612 100644
--- a/src/io/io_input.f90
+++ b/src/io/io_input.f90
@@ -94,6 +94,7 @@ subroutine io_input(infile,user)
    user%doquasimc = .false.
    user%ejecta_truncation = 10.0_DP
    user%domixing = .true.
+   user%dotopodiffusion = .true.
    write(user%sfdfile,*) trim(adjustl(SFDFILE))
    
    open(unit=LUN,file=infile,status="old",iostat=ierr)
@@ -489,6 +490,12 @@ subroutine io_input(infile,user)
             token = line(ifirst:ilast)
             read(token, *) user%dorealistic
 
+         case ("DOTOPODIFFUSION")
+            ifirst = ilast + 1
+            call io_get_token(line, ilength, ifirst, ilast, ierr)
+            token = line(ifirst:ilast)
+            read(token, *) user%dotopodiffusion
+
          !**************************************************************************
          ! The following is for backwards compatibility with older style input files
          !**************************************************************************