diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index dce1f1291b..171c8dc52a 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -17,6 +17,7 @@ This file contains a high-level description of this package's evolution. Release
 
 > Note: To avoid a conflict between `_FillValue` and `libc++18`, we have introduced a new option, `--enable-legacy-macros` for autotools and `NETCDF_ENABLE_LEGACY_MACROS` for cmake.  These are turned on by default currently but will be turned off eventually.  Developers are encouraged to move away from the `FillValue` macro and replace it with the new `NC_FillValue` macro.  See [Github #2858](https://github.com/Unidata/netcdf-c/issues/2858) for more information. 
 
+* Cleanup the blosc testing in nc_test4 and nczarr_test. See [Github #3046](https://github.com/Unidata/netcdf-c/pull/3046) for more information.
 * Provide better documentation for the .rc file mechanism and API. See [Github #2956](https://github.com/Unidata/netcdf-c/pull/2956) for more information.
 * Convert NCZarr V2 to store all netcdf-4 specific info as attributes. This improves interoperability with other Zarr implementations by no longer using non-standard keys. The price to be paid is that lazy attribute reading cannot be supported. See [Github #2836](https://github.com/Unidata/netcdf-c/pull/2936) for more information.
 * Cleanup the option code for NETCDF_ENABLE_SET_LOG_LEVEL\[_FUNC\] See [Github #2931](https://github.com/Unidata/netcdf-c/pull/2931) for more information.
diff --git a/nc_test4/tst_specific_filters.sh b/nc_test4/tst_specific_filters.sh
index 64333edaa0..d4e5375f1b 100755
--- a/nc_test4/tst_specific_filters.sh
+++ b/nc_test4/tst_specific_filters.sh
@@ -17,13 +17,13 @@ THISDIR=`pwd`
 cd $ISOPATH
 fi
 
-if test "x$TESTNCZARR" = x1 ; then
-BLOSCARGS="32001,0,0,0,256,5,1,1"
-BLOSCCODEC='[{\"id\": \"blosc\",\"clevel\": 5,\"blocksize\": 256,\"cname\": \"lz4\",\"shuffle\": 1}]'
-else
+if test"x$FP_ISMINGW" == xyes || test"x$FP_ISMSYS" == xyes || test"x$FP_ISMSVC" == xyes ; then
 BLOSCARGS="32001,0,0,4,256,5,1,1"
-BLOSCCODEC='[{\"id\": \"blosc\",\"clevel\": 5,\"blocksize\": 256,\"cname\": \"lz4\",\"shuffle\": 1}]'
+else
+BLOSCARGS="32001,0,0,0,256,5,1,1"
 fi
+BLOSCARGSALT="32001,0,0,4,256,5,1,1"
+BLOSCCODEC='[{\"id\": \"blosc\",\"clevel\": 5,\"blocksize\": 256,\"cname\": \"lz4\",\"shuffle\": 1}]'
 
 # Load the findplugins function
 . ${builddir}/findplugin.sh
@@ -157,6 +157,12 @@ testblosc() {
   zext=$1
   if ! avail blosc; then return 0; fi
   runfilter $zext blosc $BLOSCARGS "$BLOSCCODEC"
+  # Need to ignore the first three parameters by setting them to 0
+if test 1 = 0 ; then
+  sed -e "s|${BLOSCARGSALT}|${BLOSCARGS}|" < tmp_filter_blosc.dump > tmp.dump
+  rm -f tmp_filter_blosc.dump
+  mv -f tmp.dump tmp_filter_blosc.dump
+fi
   diff -b -w "tmp_filt_blosc.cdl" "tmp_filt_blosc.dump"
 }