diff --git a/doc/ChangeLog b/doc/ChangeLog
index ff2ea7f207..71b07aa2f2 100644
--- a/doc/ChangeLog
+++ b/doc/ChangeLog
@@ -1,8 +1,6 @@
-===============================================================
-Tag name: ctsm5.2.012
 Originator(s): samrabin (Sam Rabin, UCAR/TSS, samrabin@ucar.edu)
 	       glemieux (Gregory Lemieux, LBNL, glemieux@lbl.gov)
-Date: Mon 15 Jul 2024 10:50:00 AM MDT
+Date: Wed 17 Jul 2024 01:20:00 PM MDT
 One-line Summary: FATES Land Use V2
 
 Purpose and description of changes
@@ -33,6 +31,7 @@ Does this tag change answers significantly for any of the following physics conf
 
 [ ] clm4_5
 
+
 Notes of particular relevance for users
 ---------------------------------------
 
@@ -78,6 +77,16 @@ Changes to tests or testing:
    and use_fates_lupft namelist options.  Additoinally a new system text prefix,
    PVT, has been added to test the use_fates_potentialveg spin-up to use_fates_lupft
    transient workflow.  These have been added to the fates test suite.
+=======
+
+Bugs fixed
+----------
+List of CTSM issues fixed (include CTSM Issue # and description) [one per line]:
+Fixes #2444 Failing water isotope test on the ctsm5.2 branch
+
+Notes of particular relevance for users
+---------------------------------------
+Changes to documentation: None
 
 Testing summary:
 ----------------
@@ -97,9 +106,9 @@ Testing summary:
 If the tag used for baseline comparisons was NOT the previous tag, note that here:
    fates tested against fates-sci.1.76.4_api.35.1.0-ctsm5.2.008
 
+
 Answer changes
 --------------
-
 Changes answers relative to baseline: Only for FATES test mods, otherwise B4B
 
 Other details
@@ -112,6 +121,59 @@ Pull Requests that document the changes (include PR ids):
  #2507 -- FATES land use v2 API update (CTSM-side)
  NGEET#1116 -- V2 Land Use Change
 
+===============================================================
+===============================================================
+Tag name: ctsm5.2.012
+Originator(s): sacks (Bill Sacks, UCAR/NCAR/CGD)
+Date: Tue 16 Jul 2024 08:57:42 AM MDT
+One-line Summary: Relax tolerance for truncating small snocan values in CanopyFluxes
+
+Purpose and description of changes
+----------------------------------
+
+Details in the PR #2457.
+
+
+Significant changes to scientifically-supported configurations
+--------------------------------------------------------------
+
+Does this tag change answers significantly for any of the following physics configurations?
+(Details of any changes will be given in the "Answer changes" section below.)
+
+    [Put an [X] in the box for any configuration with significant answer changes.]
+
+[ ] clm6_0
+
+[ ] clm5_1
+
+[ ] clm5_0
+
+[ ] ctsm5_0-nwp
+
+[ ] clm4_5
+
+ [PASS means all tests PASS; OK means tests PASS other than expected fails.]
+
+  regular tests (aux_clm: https://github.com/ESCOMP/CTSM/wiki/System-Testing-Guide#pre-merge-system-testing):
+
+    derecho ----- OK
+    izumi ------- OK
+
+Answer changes
+--------------
+
+Changes answers relative to baseline:
+ Yes, roundoff.
+
+    - what code configurations: All
+    - what platforms/compilers: All
+    - nature of change: Changes start roundoff level and grow over time.
+
+Other details
+-------------
+Pull Requests that document the changes (include PR ids):
+ https://github.com/ESCOMP/ctsm/pull/2457
+
 ===============================================================
 ===============================================================
 Tag name: ctsm5.2.011
diff --git a/doc/ChangeSum b/doc/ChangeSum
index 269eea1f09..92ca8281cf 100644
--- a/doc/ChangeSum
+++ b/doc/ChangeSum
@@ -1,6 +1,7 @@
 Tag                   Who      Date  Summary
 ============================================================================================================================
-       ctsm5.2.012 glemieux 07/15/2024 FATES Land Use V2
+       ctsm5.2.013 glemieux 07/17/2024 FATES Land Use V2
+       ctsm5.2.012    sacks 07/16/2024 Relax tolerance for truncating small snocan values in CanopyFluxes
        ctsm5.2.011   slevis 07/12/2024 Merge b4b-dev
        ctsm5.2.010 multiple 07/11/2024 Explicit A/C adoption
        ctsm5.2.009     erik 07/10/2024 Allow for CAM7 in lnd_tuning_mode and handle C or E in long compset names
diff --git a/src/biogeophys/CanopyFluxesMod.F90 b/src/biogeophys/CanopyFluxesMod.F90
index 58334a70c0..a969dc0583 100644
--- a/src/biogeophys/CanopyFluxesMod.F90
+++ b/src/biogeophys/CanopyFluxesMod.F90
@@ -1624,7 +1624,8 @@ subroutine CanopyFluxes(bounds,  num_exposedvegp, filter_exposedvegp,
       ! snocan < rel_epsilon * snocan_baseline will be set to zero
       ! See NumericsMod for rel_epsilon value
       call truncate_small_values(fn, filterp, begp, endp, &
-         snocan_baseline(begp:endp), snocan(begp:endp))
+         snocan_baseline(begp:endp), snocan(begp:endp), &
+         custom_rel_epsilon=1.e-10_r8)
       
       if ( use_fates ) then