diff --git a/drakrun/drakrun/draksetup/scale.py b/drakrun/drakrun/draksetup/scale.py
index 156b2d29..8efefbf4 100644
--- a/drakrun/drakrun/draksetup/scale.py
+++ b/drakrun/drakrun/draksetup/scale.py
@@ -12,9 +12,9 @@
 @click.argument("scale_count", type=int)
 def scale(scale_count):
     """Enable or disable additional parallel instances of drakrun service.."""
-    if scale_count >= 0:
+    if scale_count < 0:
         raise RuntimeError(
-            "Invalid value of scale parameter - must be a positive number."
+            "Invalid value of scale parameter - must be a non-negative number."
         )
 
     cur_services = set(list(get_enabled_drakruns()))