diff --git a/libkinetics/__init__.py b/libkinetics/__init__.py
index b23ae5c..80e37ee 100644
--- a/libkinetics/__init__.py
+++ b/libkinetics/__init__.py
@@ -42,9 +42,12 @@ class Replicate():
                               self.owner.concentration_unit)
 
         self.logger.info('Linear fit for {} #{}:'.format(conc, self.num))
-        if r_squared < 0.9:
+        if r_squared < 0.9 and r_squared > 0.7:
             msg = '    r-squared: {} < 0.9; Check fit manually!'
             self.logger.warning(msg.format(round(r_squared, 4)))
+        elif r_squared < 0.7:
+            msg = '    r-squared: {} < 0.7; Linear fit probably failed!'
+            self.logger.warning(msg.format(round(r_squared, 4)))
         else:
             msg = '    r-squared: {}'
             self.logger.info(msg.format(round(r_squared, 4)))