diff --git a/src/AnalysisPrograms/Sandpit.cs b/src/AnalysisPrograms/Sandpit.cs
index 45d052a79..0988df80d 100644
--- a/src/AnalysisPrograms/Sandpit.cs
+++ b/src/AnalysisPrograms/Sandpit.cs
@@ -62,7 +62,7 @@ public override Task<int> Execute(CommandLineApplication app)
                 Log.WriteLine("# Start Time = " + tStart.ToString(CultureInfo.InvariantCulture));
 
                 //AnalyseFrogDataSet();
-                //Audio2CsvOverOneFile();
+                Audio2CsvOverOneFile();
                 //Audio2CsvOverMultipleFiles();
 
                 // used to get files from availae for Black rail and Least Bittern papers.
@@ -89,7 +89,7 @@ public override Task<int> Execute(CommandLineApplication app)
                 //ResourcesForRheobatrachusSilusRecogniser();
                 //TestAnalyseLongRecordingUsingArtificialSignal();
                 //TestArbimonSegmentationAlgorithm();
-                TestDrawHistogram();
+                //TestDrawHistogram();
                 //TestEigenValues();
                 //TestChannelIntegrity();
                 //TestDct();
@@ -324,8 +324,8 @@ public static void Audio2CsvOverOneFile()
             //string outputPath = @"G:\SensorNetworks\Output\BradLaw\Pillaga24";
             //string configPath = @"C:\Work\GitHub\audio-analysis\AudioAnalysis\AnalysisConfigFiles\Towsey.Acoustic.yml";
 
-            string recordingPath = @"C:\Ecoacoustics\WavFiles\LizZnidersic\TasmanIsland2015_Unit2_Mez\SM304256_0+1_20151114_031652.wav";
-            string outputPath = @"C:\Ecoacoustics\Output\Test\Test24HourRecording\TasmanIslandMez\04";
+            string recordingPath = @"C:\Ecoacoustics\WavFiles\LizZnidersic\TasmanIsland2015_Unit2_Mez\SM304256_0+1_20151114_231652.wav";
+            string outputPath = @"C:\Ecoacoustics\Output\Test\Test24HourRecording\TasmanIslandMez\24";
             string configPath = @"C:\Work\GitHub\audio-analysis\src\AnalysisConfigFiles\Towsey.Acoustic.yml";
 
             // Ivan Campos recordings
diff --git a/src/AudioAnalysisTools/LongDurationSpectrograms/LDSpectrogramRGB.cs b/src/AudioAnalysisTools/LongDurationSpectrograms/LDSpectrogramRGB.cs
index afca1babe..f233c051a 100644
--- a/src/AudioAnalysisTools/LongDurationSpectrograms/LDSpectrogramRGB.cs
+++ b/src/AudioAnalysisTools/LongDurationSpectrograms/LDSpectrogramRGB.cs
@@ -467,10 +467,19 @@ public void LoadSpectrogramDictionary(Dictionary<string, double[,]> dictionary)
             // check if user wants to use the automated bounds.
             if (this.IndexStats != null)
             {
+                // get the stats for this key
+                var stats = this.IndexStats[key];
                 if (indexProperties.CalculateNormMin)
                 {
-                    //min = this.IndexStats[key].Mode;
-                    minBound = this.IndexStats[key].Mode - (this.IndexStats[key].StandardDeviation * 0.1);
+                    // By default the minimum bound is set slightly below the modal value of the index.
+                    minBound = stats.Mode - (stats.StandardDeviation * 0.1);
+
+                    // case where mode = min. Usually this occurs when mode = 0.0.
+                    if (stats.Mode < 0.001)
+                    {
+                        var binWidth = (stats.Maximum - stats.Minimum) / stats.Distribution.Length;
+                        minBound += binWidth;
+                    }
 
                     // fix case where signal is defective &= zero. We do not want ACI min ever set too low.
                     if (key.Equals("ACI") && minBound < 0.3)
@@ -487,12 +496,12 @@ public void LoadSpectrogramDictionary(Dictionary<string, double[,]> dictionary)
 
                 if (indexProperties.CalculateNormMax)
                 {
-                    maxBound = this.IndexStats[key].GetValueOfNthPercentile(IndexDistributions.UpperPercentileDefault);
+                    maxBound = stats.GetValueOfNthPercentile(IndexDistributions.UpperPercentileDefault);
 
                     // correct for case where max bound = zero. This can happen where ICD is very short i.e. 0.1s.
                     if (maxBound < 0.0001)
                     {
-                        maxBound = this.IndexStats[key].Maximum * 0.1;
+                        maxBound = stats.Maximum * 0.1;
                     }
                 }
 
@@ -621,7 +630,7 @@ public void DrawNegativeFalseColourSpectrogram(DirectoryInfo outputDirectory, st
         /// <summary>
         /// Draw a chromeless false colour spectrogram.
         /// Chromeless means WITHOUT all the trimmings, such as title bar axis labels, grid lines etc.
-        /// However it does add in notated error segments
+        /// However it does add in notated error segments.
         /// </summary>
         public Image DrawFalseColourSpectrogramChromeless(string colorMode, string colorMap)
         {
diff --git a/src/TowseyLibrary/GraphsAndCharts.cs b/src/TowseyLibrary/GraphsAndCharts.cs
index c2c63920b..946e374d6 100644
--- a/src/TowseyLibrary/GraphsAndCharts.cs
+++ b/src/TowseyLibrary/GraphsAndCharts.cs
@@ -47,9 +47,7 @@ public static Image DrawHistogram(string label, int[] histogram, int upperPercen
             g.DrawLine(pen1, 0, height - 1, imageWidth, height - 1);
 
             // draw upper percentile bound
-            g.DrawLine(pen4, upperBound, height - 1, upperBound, 0);
-
-            g.DrawString(label, stringFont, Brushes.Wheat, new PointF(4, 3));
+            g.DrawLine(pen4, upperBound, height - 1, upperBound, height / 3);
 
             if (statistics != null)
             {
@@ -88,8 +86,9 @@ public static Image DrawHistogram(string label, int[] histogram, int upperPercen
                 g.FillRectangle(brush, x, height - y, barWidth, y);
             }
 
-            // draw mode bin
-            g.DrawLine(pen4, modeBin, height - 1, modeBin, 0);
+            // draw label and modal bin
+            g.DrawString(label, stringFont, Brushes.Wheat, new PointF(4, 3));
+            g.DrawLine(pen4, modeBin, height - 1, modeBin, height / 3);
 
             return bmp;
         }