diff --git a/rowers/dataroutines.py b/rowers/dataroutines.py
index 31129951..2e8e4c5c 100644
--- a/rowers/dataroutines.py
+++ b/rowers/dataroutines.py
@@ -1259,7 +1259,6 @@ def getsmallrowdata_db(columns, ids=[], doclean=True, workstrokesonly=True, comp
             df = pd.concat(data, axis=0)
         except ValueError:  # pragma: no cover
             return pd.DataFrame()
-        # df = dd.concat(data,axis=0)
 
     else:
         try:
diff --git a/rowers/interactiveplots.py b/rowers/interactiveplots.py
index a3dc27bf..c1fa8eaf 100644
--- a/rowers/interactiveplots.py
+++ b/rowers/interactiveplots.py
@@ -6283,7 +6283,15 @@ def thumbnails_set(r, id, favorites):
     columns += ['time']
     rowdata = dataprep.getsmallrowdata_db(columns, ids=[id], doclean=True)
 
-    rowdata.dropna(axis=1, how='all', inplace=True)
+    try:
+        rowdata.dropna(axis=1, how='all', inplace=True)
+    except TypeError:
+        return [
+            {'script': "",
+             'div': "",
+             'notes': ""
+             }]
+        
 
     if rowdata.empty:
         try:
@@ -6303,12 +6311,6 @@ def thumbnails_set(r, id, favorites):
              'notes': ""
              }]
 
-    #    else:
-    #        try:
-    #            rowdata.sort_values(by='time',ascending=True,inplace=True)
-    #        except KeyError:
-    #            pass
-
     lengte = len(rowdata)
     maxlength = 50
     if lengte > maxlength:
diff --git a/rowers/models.py b/rowers/models.py
index bcbfdf6e..e533f129 100644
--- a/rowers/models.py
+++ b/rowers/models.py
@@ -964,6 +964,7 @@ class Rower(models.Model):
     # Power Zone Data
     ftp = models.IntegerField(
         default=226, verbose_name="Functional Threshold Power")
+    cogganzones = models.BooleanField(verbose_name='Use Default Power Zones',default=True)
 
     p0 = models.FloatField(default=1.0, verbose_name="CP p1")
     p1 = models.FloatField(default=1.0, verbose_name="CP p2")
@@ -997,11 +998,11 @@ class Rower(models.Model):
     pw_an = models.IntegerField(default=273, verbose_name="AN Power")
 
     powerzones = PowerZonesField(default=['Rest',
-                                          'Pwr UT2',
-                                          'Pwr UT1',
-                                          'Pwr AT',
-                                          'Pwr TR',
-                                          'Pwr AN'])
+                                          'Active Recovery',
+                                          'Endurance',
+                                          'Tempo',
+                                          'Threshold',
+                                          'Anaerobic'])
 
     hrzones = PowerZonesField(default=['Rest',
                                        'UT2',
@@ -4224,7 +4225,7 @@ class RowerExportForm(ModelForm):
 class RowerPowerForm(ModelForm):
     class Meta:
         model = Rower
-        fields = ['hrftp', 'ftp', 'otwslack']
+        fields = ['hrftp', 'ftp', 'otwslack','cogganzones']
 
 
 class RowerCPForm(ModelForm):
diff --git a/rowers/templates/rower_preferences.html b/rowers/templates/rower_preferences.html
index 28f27dc2..ba9456ad 100644
--- a/rowers/templates/rower_preferences.html
+++ b/rowers/templates/rower_preferences.html
@@ -10,6 +10,103 @@
 <p><a href="http://analytics.rowsandall.com/2017/11/02/rowsandall-settings-page-tutorial/">Need help? Click to read the tutorial</a></p>
 
 <ul class="main-content">
+  <li class="grid_2">
+  <form enctype="multipart/form-data" action="" method="post">
+    <h2>Functional Threshold Power and OTW Slack</h2>
+    <p>Use this form to quickly change your zones based on the power
+      of a recent full out 60 minutes effort on the ergometer.  It
+      will update all zones defined.</p>
+    <p>The OTW Power Slack is the percentage drop of your On-the-water
+      rowing power vs the erg power. Typical values are around
+      15%. This will lower the power zones for your OTW workouts.</p>
+    <p>If you use default power zones, we will use the namees and
+      values as defined by
+      <a href="https://www.trainingpeaks.com/blog/power-training-levels/" target="_">Coggan</a>.</p>
+        <table>
+	{{ powerform.as_table }}
+      </table>
+      {% csrf_token %}
+      <input type="submit" value="Update">
+  </form>
+  </li>
+  <li class="grid_2">
+    <h2>Power Zones</h2>
+    <p>Use this form if you want to rename and redefine your power
+    zones independent of the value of FTP. We recommend, however, that
+    you leave these values as they are and only change the FTP and OTW
+    slack values.</p>
+    <form enctype="multipart/form-data" action="" method="post">
+      {% if powerzonesform.errors %}
+      <p style="color: red;">
+        Please correct the error{{ powerzonesform.errors|pluralize }} below.
+        {{ powerzonesform.non_field_errors }}
+
+      </p>
+      {% endif %}
+      <table>
+        <thead>
+          <tr>
+            <th>ID&nbsp;</th><th>Zone Name</th><th>Lower Boundary (Watt)&nbsp;</th><th>Lower Boundary (Watt)</th>
+	  </tr>
+	  <tr>
+	    <th></th><th></th><th>Indoor</th><th>OTW</th>
+          </tr>
+        </thead>
+        <tbody>
+          <tr>
+            <td>1</td><td>{{ powerzonesform.ut3name }}</td>
+            <td></td>
+          </tr>
+          <tr>
+            <td>2</td><td>{{ powerzonesform.ut2name }}</td>
+            <td>{{ powerzonesform.pw_ut2 }}</td>
+            <td>{{ user.rower.pw_ut2|otwslack:user }}</td>
+          </tr>
+          <tr>
+            <td>3</td><td>{{ powerzonesform.ut1name }}</td>
+            <td>{{ powerzonesform.pw_ut1 }}</td>
+            <td>{{ user.rower.pw_ut1|otwslack:user }}</td>
+          </tr>
+          <tr>
+            <td>4</td><td>{{ powerzonesform.atname }}</td>
+            <td>{{ powerzonesform.pw_at }}</td>
+            <td>{{ user.rower.pw_at|otwslack:user }}</td>
+          </tr>
+          <tr>
+            <td>5</td><td>{{ powerzonesform.trname }}</td>
+            <td>{{ powerzonesform.pw_tr }}</td>
+            <td>{{ user.rower.pw_tr|otwslack:user }}</td>
+          </tr>
+          <tr>
+            <td>6</td><td>{{ powerzonesform.anname }}</td>
+            <td>{{ powerzonesform.pw_an }}</td>
+            <td>{{ user.rower.pw_an|otwslack:user }}</td>
+          </tr>
+        </tbody>
+      </table>
+      {% csrf_token %}
+      <div class="grid_2 prefix_2 suffix_2">
+        <input type="submit" value="Update Power Zones">
+      </div>
+    </form>
+  </li>
+  <li class="grid_2">
+    <form enctype="multipart/form-data" action="" method="post">
+      <h2>Fitness and Performance Manager Settings</h2>
+      <p>Use this form to change the parameters affecting your performance management.</p>
+      <p>A shorter range for the CP calculations
+	will give you notifications of fitness improvements more often,
+	but will also quickly forget those breakthrough workouts. Shorter decay
+	time constants for the performance manager will model a quicker building up
+	of fitness and a faster recovery. Recommended values are 42 days (fitness)
+	and 7 days (fatigue).</p>
+      <table>
+	{{ cpform.as_table }}
+      </table>
+      {% csrf_token %}
+      <input type="submit" value="Update">
+    </form>
+  </li>
   <li class="grid_2">
     <p>
       <h2>Heart Rate Zones</h2>
@@ -22,7 +119,7 @@
     </p>
     {% endif %}
       <table>
-				<thead>
+	<thead>
           <tr>
             <th>ID</th><th>Zone Name</th><th>Lower Boundary (BPM)</th>
           </tr>
@@ -52,7 +149,7 @@
             <td>6</td><td>{{ form.hranname }}</td>
             <td>{{ form.an }}</td>
           </tr>
-					<tr>
+	  <tr>
             <td>7</td><td>{{ form.hrmaxname }}</td>
             <td>{{ form.max }}</td>
           </tr>
@@ -62,92 +159,6 @@
       <input type="submit" value="Update Heart Rate Zones">
     </form>
   </li>
-  <li class="grid_2">
-    <h2>Power Zones</h2>
-    <p>The power zones are defined relative to power as measured by the
-      indoor rower.</p>
-    <form enctype="multipart/form-data" action="" method="post">
-      {% if powerzonesform.errors %}
-      <p style="color: red;">
-        Please correct the error{{ powerzonesform.errors|pluralize }} below.
-        {{ powerzonesform.non_field_errors }}
-
-      </p>
-      {% endif %}
-      <table>
-        <thead>
-          <tr>
-            <th>ID</th><th>Zone Name</th><th>Lower Boundary (Watt)</th>
-          </tr>
-        </thead>
-        <tbody>
-          <tr>
-            <td>1</td><td>{{ powerzonesform.ut3name }}</td>
-            <td></td>
-          </tr>
-          <tr>
-            <td>2</td><td>{{ powerzonesform.ut2name }}</td>
-            <td>{{ powerzonesform.pw_ut2 }}</td>
-          </tr>
-          <tr>
-            <td>3</td><td>{{ powerzonesform.ut1name }}</td>
-            <td>{{ powerzonesform.pw_ut1 }}</td>
-          </tr>
-          <tr>
-            <td>4</td><td>{{ powerzonesform.atname }}</td>
-            <td>{{ powerzonesform.pw_at }}</td>
-          </tr>
-          <tr>
-            <td>5</td><td>{{ powerzonesform.trname }}</td>
-            <td>{{ powerzonesform.pw_tr }}</td>
-          </tr>
-          <tr>
-            <td>6</td><td>{{ powerzonesform.anname }}</td>
-            <td>{{ powerzonesform.pw_an }}</td>
-          </tr>
-        </tbody>
-      </table>
-      {% csrf_token %}
-      <div class="grid_2 prefix_2 suffix_2">
-        <input type="submit" value="Update Power Zones">
-      </div>
-    </form>
-  </li>
-  <li class="grid_2">
-  <form enctype="multipart/form-data" action="" method="post">
-    <h2>Functional Threshold Power and OTW Slack</h2>
-    <p>Use this form to quickly change your zones based on the power of a
-      recent
-      full out 60 minutes effort on the ergometer.
-      It will update all zones defined above.</p>
-    <p>The OTW Power Slack is the percentage drop of your On-the-water
-      rowing power
-      vs the erg power. Typical values are around 15%. This will lower
-      the power zones for your OTW workouts.</p>
-        <table>
-	{{ powerform.as_table }}
-      </table>
-      {% csrf_token %}
-      <input type="submit" value="Update">
-  </form>
-  </li>
-	<li class="grid_2">
-	<form enctype="multipart/form-data" action="" method="post">
-		<h2>Fitness and Performance Manager Settings</h2>
-		<p>Use this form to change the parameters affecting your performance management.</p>
-		<p>A shorter range for the CP calculations
-			will give you notifications of fitness improvements more often,
-		but will also quickly forget those breakthrough workouts. Shorter decay
-	time constants for the performance manager will model a quicker building up
-of fitness and a faster recovery. Recommended values are 42 days (fitness)
-and 7 days (fatigue).</p>
-				<table>
-	{{ cpform.as_table }}
-			</table>
-			{% csrf_token %}
-			<input type="submit" value="Update">
-	</form>
-	</li>
 </ul>
 
 
diff --git a/rowers/templatetags/rowerfilters.py b/rowers/templatetags/rowerfilters.py
index a1e234ab..40924683 100644
--- a/rowers/templatetags/rowerfilters.py
+++ b/rowers/templatetags/rowerfilters.py
@@ -1039,3 +1039,8 @@ def previousworkout(workout, user):
         return encoder.encode_hex(ws[0].id)
     else:
         return 0
+
+@register.filter
+def otwslack(value, user):
+    r = Rower.objects.get(user=user)
+    return int(value*(100.-r.otwslack)/100.)
diff --git a/rowers/views/userviews.py b/rowers/views/userviews.py
index 6f1492e9..cd744ffd 100644
--- a/rowers/views/userviews.py
+++ b/rowers/views/userviews.py
@@ -618,13 +618,23 @@ def rower_prefs_view(request, userid=0, message=""):
                 hrftp = int((r.an+r.tr)/2.)
             ftp = cd['ftp']
             otwslack = cd['otwslack']
+            cogganzones = cd['cogganzones']
 
             powerfrac = 100*np.array([r.pw_ut2,
                                       r.pw_ut1,
                                       r.pw_at,
                                       r.pw_tr, r.pw_an])/r.ftp
+            if cogganzones:
+                powerfrac = np.array([55.,75.,90.,105.,120.])
+                powerzones = ['Rest',
+                          'Active Recovery',
+                          'Endurance',
+                          'Tempo',
+                          'Threshold',
+                          'Anaerobic']
+                r.powerzones = powerzones
+
             r.ftp = max(min(ftp, 650), 50)
-            r.otwslack = max(min(otwslack, 50), 0)
             ut2, ut1, at, tr, an = (r.ftp*powerfrac/100.).astype(int)
             r.pw_ut2 = ut2
             r.pw_ut1 = ut1
@@ -632,7 +642,10 @@ def rower_prefs_view(request, userid=0, message=""):
             r.pw_tr = tr
             r.pw_an = an
             r.hrftp = hrftp
+            r.otwslack = max(min(otwslack, 50), 0)
             r.save()
+            powerzonesform = RowerPowerZonesForm(instance=r)
+
             message = "FTP and/or OTW slack values changed."
             messages.info(request, message)