diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ActivityAnalysis.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ActivityAnalysis.java
index 2ab4f50d..db82772d 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ActivityAnalysis.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ActivityAnalysis.java
@@ -21,25 +21,21 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityAmount;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityAmounts;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivityKind;
 import nodomain.freeyourgadget.gadgetbridge.model.ActivitySample;
 
 class ActivityAnalysis {
+    private static final Logger LOG = LoggerFactory.getLogger(ActivityAnalysis.class);
+
     // store raw steps and duration
     protected HashMap<Integer, Long> stats = new HashMap<Integer, Long>();
-    // normalize steps
-    protected HashMap<Float, Float> statsQuantified = new HashMap<Float, Float>();
-    // store maxSpeed / resolution
-    protected float maxSpeedQuantifier;
-    // store an average of round precision
-    protected float roundPrecision = 0f;
-
     // max speed determined from samples
     private int maxSpeed = 0;
-    // number of bars on stats chart
-    private int resolution = 5;
 
     ActivityAmounts calculateActivityAmounts(List<? extends ActivitySample> samples) {
         ActivityAmount deepSleep = new ActivityAmount(ActivityKind.TYPE_DEEP_SLEEP);
@@ -89,11 +85,11 @@ class ActivityAnalysis {
                     }
 
                     if (!stats.containsKey(steps)) {
-                        //System.out.println("Adding: " + steps);
+                        LOG.info("Adding: " + steps);
                         stats.put(steps, timeDifference);
                     } else {
                         long time = stats.get(steps);
-                        //System.out.println("Updating: " + steps + " " + timeDifference + time);
+                        LOG.info("Updating: " + steps + " " + timeDifference + time);
                         stats.put(steps, timeDifference + time);
                     }
                 }
@@ -103,34 +99,6 @@ class ActivityAnalysis {
             previousSample = sample;
         }
 
-        maxSpeedQuantifier = maxSpeed / resolution;
-        for (Map.Entry<Integer, Long> entry : stats.entrySet()) {
-            // 0.1 precision
-            //float keyQuantified = Math.round(entry.getKey() / maxSpeedQuantifier * 10f) / 10f;
-
-            // 1 precision
-            float keyQuantified = entry.getKey() / maxSpeedQuantifier;
-            float keyQuantifiedRounded = Math.round(entry.getKey() / maxSpeedQuantifier);
-            float keyQuantifiedPrecision = keyQuantifiedRounded - keyQuantified;
-            roundPrecision = (roundPrecision + Math.abs(keyQuantifiedPrecision)) / 2;
-            //System.out.println("Precision: " + roundPrecision);
-
-            // no scale
-            //keyQuantified = entry.getKey();
-
-            // scaling to minutes
-            float timeMinutes = entry.getValue() / 60;
-
-            if (!statsQuantified.containsKey(keyQuantifiedRounded)) {
-                //System.out.println("Adding: " + keyQuantified + "/" + timeMinutes);
-                statsQuantified.put(keyQuantifiedRounded, timeMinutes);
-            } else {
-                float previousTime = statsQuantified.get(keyQuantifiedRounded);
-                //System.out.println("Updating: " + keyQuantified + "/" + (timeMinutes + previousTime));
-                statsQuantified.put(keyQuantifiedRounded, (timeMinutes + previousTime));
-            }
-        }
-
         ActivityAmounts result = new ActivityAmounts();
         if (deepSleep.getTotalSeconds() > 0) {
             result.addAmount(deepSleep);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ChartsActivity.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ChartsActivity.java
index 9b6afee5..2cfb018f 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ChartsActivity.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/ChartsActivity.java
@@ -338,12 +338,12 @@ public class ChartsActivity extends AbstractGBFragmentActivity implements Charts
 
         @Override
         public int getCount() {
-            // Show 4 or 5 total pages. (always hide speed zones)
+            // Show 5 or 6 total pages.
             DeviceCoordinator coordinator = DeviceHelper.getInstance().getCoordinator(mGBDevice);
             if (coordinator.supportsRealtimeData()) {
-                return 5;
+                return 6;
             }
-            return 4;
+            return 5;
         }
 
         @Override
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/XAxisValueFormatter.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/XAxisValueFormatter.java
index ecaae223..30d875ea 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/XAxisValueFormatter.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/charts/XAxisValueFormatter.java
@@ -19,15 +19,19 @@ package nodomain.freeyourgadget.gadgetbridge.activities.charts;
 import com.github.mikephil.charting.components.AxisBase;
 import com.github.mikephil.charting.formatter.IAxisValueFormatter;
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 
 /**
- * Created by nhu on 30/04/17.
+ * Created by Vebryn on 30/04/17.
  */
 
 public class XAxisValueFormatter implements IAxisValueFormatter {
+    private static final Logger LOG = LoggerFactory.getLogger(XAxisValueFormatter.class);
     private List<String> mValues = new ArrayList<>();
 
     public XAxisValueFormatter() {
@@ -39,7 +43,7 @@ public class XAxisValueFormatter implements IAxisValueFormatter {
     }
 
     public void sort() {
-        //System.out.println("Sorting " + mValues);
+        LOG.info("Sorting " + mValues);
         Collections.sort(mValues);
     }
 
@@ -49,9 +53,9 @@ public class XAxisValueFormatter implements IAxisValueFormatter {
 
         try {
             returnString = mValues.get((int) value).toString();
-            //System.out.println("Asking " + value + ", returning " + returnString);
+            LOG.info("Asking " + value + ", returning " + returnString);
         } catch (Exception e) {
-            System.out.println(e.getMessage());
+            LOG.error(e.getMessage());
         }
         return returnString;
     }