diff --git a/backup-zfs b/backup-zfs
index 92fd708..a6d200c 100755
--- a/backup-zfs
+++ b/backup-zfs
@@ -2,14 +2,14 @@
 # backup-zfs: use zfs send/recv to push/pull snapshots
 
 usage() {
-	echo "$(basename "$0") [-hvq] [-t tag] [-k keep] [-f dateformat] [srchost:]srcfs [desthost:]destfs" >&2
+	echo "$(basename "$0") [-hvq] [-t tag] [-k keep] [-d dateopts] [srchost:]srcfs [desthost:]destfs" >&2
 	echo "$(basename "$0"): use zfs send/recv to push/pull snapshots" >&2
 	printf "%15s: %s\n" >&2 "-h" "this help statement" \
 	                        "-v" "verbose" \
 				"-q" "quiet" \
 	                    "-t tag" "tag to use for naming snapshots and in syslog" \
 	                   "-k keep" "number of snapshots to keep on src" \
-	             "-f dateformat" "format string for date(1), used in naming snapshots"
+	               "-d dateopts" "options string for date(1), used in naming snapshots"
 	exit $1
 }
 
@@ -53,7 +53,7 @@ ZFS() {
 ### defaults
 ###
 tag=backup-zfs
-dateformat="%F_%T"
+dateopts="+%F_%T"
 keep=5
 verbose=false
 quiet=false
@@ -61,19 +61,19 @@ quiet=false
 ###
 ### parse options
 ###
-while getopts "hvqk:t:f:" opt ; do
+while getopts "hvqk:t:d:" opt ; do
 	case $opt in
 		h) usage 0 ;;
 		v) verbose=true ;;
 		q) quiet=true ;;
 		k) keep=$OPTARG ;;
 		t) tag=$OPTARG ;;
-		f) dateformat=$OPTARG ;;
+		d) dateopts=$OPTARG ;;
 		*) usage 1 ;;
 	esac
 done
 shift $((OPTIND-1))
-date="$(date +"$dateformat")"
+date="$(date $dateopts)"
 
 ###
 ### parse src & dest host/fs info