diff --git a/app/src/main/java/uk/org/openseizuredetector/MainActivity.java b/app/src/main/java/uk/org/openseizuredetector/MainActivity.java
index 09e3995..f244741 100644
--- a/app/src/main/java/uk/org/openseizuredetector/MainActivity.java
+++ b/app/src/main/java/uk/org/openseizuredetector/MainActivity.java
@@ -393,11 +393,21 @@ public class MainActivity extends Activity {
                         tv.setTextColor(okTextColour);
                     }
                     // Set ProgressBars to show margin to alarm.
-                    long powerPc = mConnection.mSdServer.mSdData.roiPower * 100 /
+                    long powerPc;
+                    if (mConnection.mSdServer.mSdData.alarmThresh != 0)
+                        powerPc = mConnection.mSdServer.mSdData.roiPower * 100 /
                             mConnection.mSdServer.mSdData.alarmThresh;
-                    long specPc = 100 * (mConnection.mSdServer.mSdData.roiPower * 10 /
+                    else
+                        powerPc = 0;
+
+                    long specPc;
+                    if (mConnection.mSdServer.mSdData.specPower != 0 &&
+                            mConnection.mSdServer.mSdData.alarmRatioThresh != 0)
+                        specPc = 100 * (mConnection.mSdServer.mSdData.roiPower * 10 /
                             mConnection.mSdServer.mSdData.specPower) /
                             mConnection.mSdServer.mSdData.alarmRatioThresh;
+                    else
+                        specPc = 0;
 
                     ((TextView) findViewById(R.id.powerTv)).setText("Power = " + mConnection.mSdServer.mSdData.roiPower +
                             " (threshold = " + mConnection.mSdServer.mSdData.alarmThresh + ")");
@@ -434,7 +444,8 @@ public class MainActivity extends Activity {
 
                 }
             } catch (Exception e) {
-                Log.v(TAG, "ServerStatusRunnable: Exception - " + e.toString());
+                Log.v(TAG, "ServerStatusRunnable: Exception - ");
+                e.printStackTrace();
             }
 
             // deal with latch alarms button
diff --git a/app/src/main/java/uk/org/openseizuredetector/SdServer.java b/app/src/main/java/uk/org/openseizuredetector/SdServer.java
index 2635113..9801a2a 100644
--- a/app/src/main/java/uk/org/openseizuredetector/SdServer.java
+++ b/app/src/main/java/uk/org/openseizuredetector/SdServer.java
@@ -45,6 +45,7 @@ import android.os.Environment;
 import android.os.HandlerThread;
 import android.os.Binder;
 import android.os.IBinder;
+import android.os.Looper;
 import android.os.PowerManager;
 import android.os.PowerManager.WakeLock;
 import android.preference.PreferenceManager;
@@ -413,7 +414,7 @@ public class SdServer extends Service implements SdDataReceiver {
     /* from http://stackoverflow.com/questions/12154940/how-to-make-a-beep-in-android */
 
     /**
-     * beep for duration miliseconds, but only if mAudibleAlarm is set.
+     * beep for duration milliseconds, but only if mAudibleAlarm is set.
      */
     private void beep(int duration) {
         ToneGenerator toneG = new ToneGenerator(AudioManager.STREAM_ALARM, 100);
@@ -742,7 +743,7 @@ public class SdServer extends Service implements SdDataReceiver {
             Log.v(TAG, "startFaultTimer(): starting fault timer.");
             mFaultTimerCompleted = false;
             mFaultTimer =
-                    // conver to ms.
+                    // convert to ms.
                     new FaultTimer(mFaultTimerPeriod * 1000, 1000);
             mFaultTimer.start();
         }