diff --git a/app/configuration/controllers/date-time-controller.html b/app/configuration/controllers/date-time-controller.html
index f82b67b..8ead4c8 100644
--- a/app/configuration/controllers/date-time-controller.html
+++ b/app/configuration/controllers/date-time-controller.html
@@ -17,7 +17,7 @@
         </div>
         <div class="row column date-time__ntp-servers-wrap">
           <fieldset class="date-time__ntp-servers" ng-repeat="server in ntp.servers track by $index">
-            <label for="ntp-server{{$index+1}}">NTP Server Address {{$index+1}}</label>
+            <label for="ntp-server{{$index+1}}">NTP Server Address {{$index+1}} <span ng-if="$first">(Primary)</span></label>
             <div class="inline">
               <input id="ntp-server{{$index+1}}" type="text" ng-readonly="time_mode != 'NTP'" ng-model="server" ng-blur="ntp.servers[$index] = server" set-focus-on-new-input/>
             </div>