diff --git a/rowers/forms.py b/rowers/forms.py
index 805abc7b..d1e9d116 100644
--- a/rowers/forms.py
+++ b/rowers/forms.py
@@ -154,8 +154,8 @@ class InstrokeForm(forms.Form):
     metric = forms.ChoiceField(label='metric',choices=(('a','a'),('b','b')))
     individual_curves = forms.BooleanField(label='individual curves',initial=False,
                                            required=False)
-    spm_min = forms.IntegerField(initial=15,label='SPM Min',widget=HiddenInput)
-    spm_max = forms.IntegerField(initial=45,label='SPM Max',widget=HiddenInput)
+    spm_min = forms.FloatField(initial=15,label='SPM Min',widget=HiddenInput)
+    spm_max = forms.FloatField(initial=45,label='SPM Max',widget=HiddenInput)
     activeminutesmin = forms.FloatField(
         required=False, initial=0, widget=forms.HiddenInput())
     activeminutesmax = forms.FloatField(
diff --git a/rowers/interactiveplots.py b/rowers/interactiveplots.py
index a239928a..a3dc27bf 100644
--- a/rowers/interactiveplots.py
+++ b/rowers/interactiveplots.py
@@ -4318,6 +4318,9 @@ def instroke_interactive_chart(df,metric, workout, spm_min, spm_max,
     df_pos = (df+abs(df))/2.
     df_min = -(-df+abs(-df))/2.
 
+    if df.empty:
+        return "", "No data in selection"
+
     mean_vals = df.median().replace(0, np.nan)
     q75 = df_pos.quantile(q=0.75).replace(0,np.nan)
     q25 = df_pos.quantile(q=0.25).replace(0,np.nan)