diff --git a/docs/customizing.htm b/docs/customizing.htm
index 9ab19bbb..4713ef96 100644
--- a/docs/customizing.htm
+++ b/docs/customizing.htm
@@ -3251,7 +3251,7 @@ mv weewx.sdb_new weewx.sdb</p>
       <h1>Appendix D: Packet Types</h1>
       <p><em>Packets</em> are the raw data coming off the instrument (as opposed to
 	<em>records</em>, which are stored on the database). The observation types available 
-	in a packet are useful when setting <em><a href="usersguide.htm#QC">quality 
+	in a packet are useful when setting <em><a href="usersguide.htm#StdQC">quality 
 	    control rules</a></em> and when doing <em>
 	  <a href="usersguide.htm#Calibrate">calibrations</a></em>. </p>
       <p>They may also be useful if you are writing your own custom service. In particular,