diff --git a/docs/sources/alerting/alerting.md b/docs/sources/alerting/alerting.md
index be5d14e3e10..be640145244 100644
--- a/docs/sources/alerting/alerting.md
+++ b/docs/sources/alerting/alerting.md
@@ -42,9 +42,7 @@ QueryRange: The time range for which the query should look back.
 Aggregator: How the result should be reduced into a single value. ex avg, sum, min, max
 State: Current state of the alert OK, WARN, CRITICAL, ACKNOWLEGED.
 
-You can configure these settings in the Alerting tab on graph panels in edit mode. When the dashboard is saved the alert is created, updated based on what data you provide. If you wish to delete an alert you simply set the query to '- select query -' in the alerting tab and save the dashboard. (this will be improved within the UI later on).
-
-
+You can configure these settings in the Alerting tab on graph panels in edit mode. When the dashboard is saved the alert is created or updated based on the dashboard. If you wish to delete an alert you simply set the query to '- select query -' in the alerting tab and save the dashboard. (this will be improved within the UI later on).
 
 ## Api
 
diff --git a/public/app/plugins/panel/graph/alert_tab_ctrl.ts b/public/app/plugins/panel/graph/alert_tab_ctrl.ts
index ca5b8aa37f0..c3d4d7c1b0c 100644
--- a/public/app/plugins/panel/graph/alert_tab_ctrl.ts
+++ b/public/app/plugins/panel/graph/alert_tab_ctrl.ts
@@ -12,17 +12,23 @@ export class AlertTabCtrl {
   operators = ['>', '<', '<=', '>='];
   aggregators = ['avg', 'sum', 'min', 'max', 'median'];
 
+  defaultValues = {
+    aggregator: 'avg',
+    interval: '60s',
+    queryRange: '10m',
+    warnOperator: '>',
+    critOperator: '>',
+    queryRef: '- select query -'
+  };
+
   /** @ngInject */
   constructor($scope, private $timeout) {
     $scope.alertTab = this; //HACK ATTACK!
     this.panelCtrl = $scope.ctrl;
     this.panel = this.panelCtrl.panel;
-    this.panel.alerting = this.panel.alerting || {};
-    this.panel.alerting.aggregator = this.panel.alerting.aggregator || 'avg';
-    this.panel.alerting.interval = this.panel.alerting.interval || '60s';
-    this.panel.alerting.queryRange = this.panel.alerting.queryRange || '10m';
-    this.panel.alerting.warnOperator = this.panel.alerting.warnOperator || '>';
-    this.panel.alerting.critOperator = this.panel.alerting.critOperator || '>';
+
+    _.defaults(this.panel.alerting, this.defaultValues);
+
     var defaultTitle = (this.panelCtrl.dashboard.title + ' ' + this.panel.title + ' alert');
     this.panel.alerting.title = this.panel.alerting.title || defaultTitle;
 
@@ -35,12 +41,17 @@ export class AlertTabCtrl {
   }
 
   convertThresholdsToAlertThresholds() {
-    if (this.panel.grid && this.panel.grid.threshold1) {
+    if (this.panel.grid
+        && this.panel.grid.threshold1
+        && this.panel.alerting.warnLevel === undefined) {
       this.panel.alerting.warnOperator = '>';
       this.panel.alerting.warnLevel = this.panel.grid.threshold1;
     }
 
-    if (this.panel.grid && this.panel.grid.threshold2) {
+    if (this.panel.grid
+        && this.panel.grid.threshold2
+        && this.panel.alerting.critLevel === undefined
+       ) {
       this.panel.alerting.critOperator = '>';
       this.panel.alerting.critLevel = this.panel.grid.threshold2;
     }
@@ -48,7 +59,7 @@ export class AlertTabCtrl {
 
   markAsDeleted() {
     if (this.panel.alerting) {
-      this.panel.alerting.queryRef = this.metricTargets[0].refId;
+      this.panel.alerting = this.defaultValues;
     }
   }