diff --git a/10-50-reverse.sh b/10-50-reverse.sh
index 4ceec11..c91725b 100755
--- a/10-50-reverse.sh
+++ b/10-50-reverse.sh
@@ -49,8 +49,8 @@ do
 	Serials+=( "$serial" )
 done
 
-Serials=( $( for i in ${Serials[@]}; do echo "$i"; done | sort -rn ) )
-serial=${Serials[0]}
+serial=0
+for i in ${Serials[@]}; do serial=$((serial+i)); done )
 
 echo "$DomainZone $TTL IN SOA $ReverseServerName $ContactEMail $serial $refresh $retry $expire $minimum" > "$TempDir/$DomainZone"
 echo "$DomainZone $TTL IN NS $ReverseServerName" >> "$TempDir/$DomainZone"