diff --git a/src/regolith/regolith_streamtube_head.f90 b/src/regolith/regolith_streamtube_head.f90
index 3ed34b93..730ea1ef 100644
--- a/src/regolith/regolith_streamtube_head.f90
+++ b/src/regolith/regolith_streamtube_head.f90
@@ -66,7 +66,7 @@ subroutine regolith_streamtube_head(user,surfi,deltar,totmare,tots,age_collector
       totmare = totmare + vsgly * current(M)%comp
       recyratio = vsgly / (user%pix**2) /current(M)%thickness
       age_collector(:) = age_collector(:) + current(M)%age(:) * recyratio
-      headmeltvol = current(M)%meltfrac * vsgly * recyratio
+      headmeltvol = current(M)%meltfrac * vsgly! * recyratio
       meltinejecta = meltinejecta + headmeltvol
       distvol(:) = distvol(:) + (current(M)%meltdist(:)*vsgly)!*recyratio)
       totvol = totvol + vsgly
diff --git a/src/regolith/regolith_streamtube_lineseg.f90 b/src/regolith/regolith_streamtube_lineseg.f90
index 5dc1cb92..e8e673ba 100644
--- a/src/regolith/regolith_streamtube_lineseg.f90
+++ b/src/regolith/regolith_streamtube_lineseg.f90
@@ -84,9 +84,9 @@ subroutine regolith_streamtube_lineseg(user,surfi,thetast,ri,rip1,zmin,zmax,erad
                 recyratio        = max(ebh_recyl,0.0_DP) / current(N-1)%thickness
                 age_collector(:) = age_collector(:) + current(N-1)%age(:) * recyratio
                 vol              = vol + sum(current(N-1)%age(:)) * recyratio
-                linmelt = current(N-1)%meltfrac * (vsgly-vsh)! * recyratio
+                linmelt = current(N-1)%meltfrac * max(vsgly-vsh,0.0_DP)! * recyratio
                 meltinejecta = meltinejecta + linmelt
-                distvol(:) = distvol(:) + (current(N-1)%meltdist(:)*(vsgly-vsh))!*recyratio)
+                distvol(:) = distvol(:) + (current(N-1)%meltdist(:)*max(vsgly-vsh,0.0_DP))!*recyratio)
                 totvol = totvol + vsgly
              else if (ri <= xmints .and. rip1 > xmints) then 
                      vseg             = regolith_streamtube_volume_func(eradi,xmints,rip1,deltar)
@@ -94,9 +94,9 @@ subroutine regolith_streamtube_lineseg(user,surfi,thetast,ri,rip1,zmin,zmax,erad
                      recyratio        = max((vseg-vsh),0.0_DP) / (user%pix**2) / current(N-1)%thickness 
                      age_collector(:) = age_collector(:) + current(N-1)%age(:) * recyratio
                      vol              = vol + sum(current(N-1)%age(:)) * recyratio
-                     linmelt = current(N-1)%meltfrac * (vseg-vsh)! * recyratio
+                     linmelt = current(N-1)%meltfrac * max(vseg-vsh,0.0_DP)! * recyratio
                      meltinejecta = meltinejecta + linmelt
-                     distvol(:) = distvol(:) + (current(N-1)%meltdist(:)*(vseg-vsh))!*recyratio)
+                     distvol(:) = distvol(:) + (current(N-1)%meltdist(:)*max(vseg-vsh,0.0_DP))!*recyratio)
                      totvol = totvol + vseg
              end if
              exit
@@ -124,9 +124,9 @@ subroutine regolith_streamtube_lineseg(user,surfi,thetast,ri,rip1,zmin,zmax,erad
                   recyratio        = max((vseg-vsh),0.0_DP) / (user%pix**2) / current(N)%thickness
                   age_collector(:) = age_collector(:) + current(N)%age(:) * recyratio
                   vol              = vol + sum(current(N)%age(:)) * recyratio
-                  linmelt = current(N)%meltfrac * (vseg-vsh)! * recyratio
+                  linmelt = current(N)%meltfrac * max(vseg-vsh,0.0_DP)! * recyratio
                   meltinejecta = meltinejecta + linmelt
-                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*(vseg-vsh))!*recyratio)
+                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*max(vseg-vsh,0.0_DP))!*recyratio)
                   totvol = totvol + vseg
                end if
 
@@ -137,9 +137,9 @@ subroutine regolith_streamtube_lineseg(user,surfi,thetast,ri,rip1,zmin,zmax,erad
                   recyratio        = max((vseg-vsh),0.0_DP) / (user%pix**2) / current(N)%thickness
                   age_collector(:) = age_collector(:) + current(N)%age(:) * recyratio
                   vol              = vol + sum(current(N)%age(:)) * recyratio
-                  linmelt = current(N)%meltfrac * (vseg-vsh)! * recyratio
+                  linmelt = current(N)%meltfrac * max(vseg-vsh,0.0_DP)! * recyratio
                   meltinejecta = meltinejecta + linmelt
-                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*(vseg-vsh))!*recyratio)
+                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*max(vseg-vsh,0.0_DP))!*recyratio)
                   totvol = totvol + vseg
                end if
                !current => current%next
@@ -162,9 +162,9 @@ subroutine regolith_streamtube_lineseg(user,surfi,thetast,ri,rip1,zmin,zmax,erad
                   recyratio        = max((vseg-vsh),0.0_DP) / (user%pix**2) / current(N)%thickness
                   age_collector(:) = age_collector(:) + current(N)%age(:) * recyratio
                   vol              = vol + sum(current(N)%age(:)) * recyratio
-                  linmelt = current(N)%meltfrac * vseg! * recyratio
+                  linmelt = current(N)%meltfrac * max(vseg-vsh,0.0_DP)! * recyratio
                   meltinejecta = meltinejecta + linmelt
-                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*(vseg-vsh))!*recyratio)
+                  distvol(:) = distvol(:) + (current(N)%meltdist(:)*max(vseg-vsh,0.0_DP))!*recyratio)
                   totvol = totvol + vseg
                end if
 
diff --git a/src/regolith/regolith_subpixel_streamtube.f90 b/src/regolith/regolith_subpixel_streamtube.f90
index 3a668407..a12f0d1d 100644
--- a/src/regolith/regolith_subpixel_streamtube.f90
+++ b/src/regolith/regolith_subpixel_streamtube.f90
@@ -188,26 +188,26 @@ subroutine regolith_subpixel_streamtube(user,surfi,deltar,ri,rip1,eradi,newlayer
          !if (rrighti>max(xmints,sqrt(rm**2 - z**2))) then
          if (rrighti > xmints) then
             vsh                = regolith_shock_damage(eradi,deltar,xmints,xsfints,rrighti,rrightf)
-            recyratio          = max((vsgly2 -vsh),0.0)/ (user%pix**2) / current(N)%thickness
+            recyratio          = max((vsgly2 -vsh),0.0_DP)/ (user%pix**2) / current(N)%thickness
             age_collector(:)   = age_collector(:) + current(N)%age(:) * recyratio
             vol                = vol + sum(current(N)%age(:)) * recyratio
-            mvr                = (vsgly2-vsh) * current(N)%meltfrac! * recyratio
+            mvr                = max((vsgly2 -vsh),0.0_DP) * current(N)%meltfrac! * recyratio
             recyratio2         = recyratio
             vsh2 = vsh
          end if
 
          if (rlefti > xmints) then
             vsh                = regolith_shock_damage(eradi,deltar,xmints,xsfints,rlefti,rleftf)
-            recyratio          = max((vsgly1-vsh),0.0) / (user%pix**2) / current(N)%thickness
+            recyratio          = max((vsgly1-vsh),0.0_DP) / (user%pix**2) / current(N)%thickness
             age_collector(:)   = age_collector(:) + current(N)%age(:) * recyratio
             vol                = vol + sum(current(N)%age(:)) * recyratio
-            mvl                = (vsgly1-vsh) * current(N)%meltfrac!*recyratio
+            mvl                = max((vsgly1-vsh),0.0_DP) * current(N)%meltfrac!*recyratio
          end if
 
          !current => current%next
          meltinejecta = meltinejecta + mvl + mvr
          !distvol(:) = distvol(:) + (current(N)%meltdist(:)*((vsgly1-vsh)*recyratio)+((vsgly2-vsh2)*recyratio2))
-         distvol(:) = distvol(:) + (current(N)%meltdist(:)*((vsgly1-vsh)+(vsgly2-vsh2)))
+         distvol(:) = distvol(:) + (current(N)%meltdist(:)*(max((vsgly1-vsh),0.0_DP)+max((vsgly2-vsh),0.0_DP)))
          totvol = totvol + vsgly1 + vsgly2
          !N = N - 1
          z = z + current(N-1)%thickness 
diff --git a/src/regolith/regolith_traverse_streamtube.f90 b/src/regolith/regolith_traverse_streamtube.f90
index 3ffc37a6..31e13150 100644
--- a/src/regolith/regolith_traverse_streamtube.f90
+++ b/src/regolith/regolith_traverse_streamtube.f90
@@ -89,8 +89,8 @@ subroutine regolith_traverse_streamtube(user,surfi,deltar,ri,rip1,eradi,erado,ne
          vsh              = regolith_shock_damage(eradi,deltar,xmints,xsfints,ri,rip1)
          recyratio        = max(vseg-vsh,0.0_DP) / (user%pix**2) / surfi%regolayer(N)%thickness
          age_collector(:) = age_collector(:) + surfi%regolayer(N)%age(:) * recyratio
-         meltinejecta     = meltinejecta + surfi%regolayer(N)%meltfrac*(vseg-vsh)!*recyratio
-         distvol(:)       = distvol(:) + (surfi%regolayer(N)%meltdist(:)*(vseg-vsh))!*recyratio)
+         meltinejecta     = meltinejecta + surfi%regolayer(N)%meltfrac*max(vseg-vsh,0.0_DP)!*recyratio
+         distvol(:)       = distvol(:) + (surfi%regolayer(N)%meltdist(:)*max(vseg-vsh,0.0_DP))!*recyratio)
          totvol = totvol + vseg
       end if