diff --git a/parabolic_alarm.yaml b/parabolic_alarm.yaml
index 11d3bf1..7291795 100644
--- a/parabolic_alarm.yaml
+++ b/parabolic_alarm.yaml
@@ -66,7 +66,7 @@ blueprint:
       default: 10
       selector:
         number:
-          min: 1.0
+          min: 0.0
           max: 60.0
           step: 1.0
           mode: slider
@@ -171,11 +171,17 @@ blueprint:
           mode: slider
       default: 5
   source_url: https://github.com/steku/ha_cercadian_alarm/blob/main/parabolic_alarm.yaml
+trigger_variables:
+  input_alarm_length_1: !input alarm_length_1
+  input_alarm_length_2: !input alarm_length_2
+  input_alarm_length_3: !input alarm_length_3
+  input_complete_at_start_time: !input complete_at_start_time
+  calculated_runtime: "{{ -(input_alarm_length_1 + input_alarm_length_2 + input_alarm_length_3)*60 if input_complete_at_start_time else 0 }}"
 trigger:
   - trigger: time
     at: 
       entity_id: !input alarm_start_time
-      offset: "{{ -(alarm_length_1 + alarm_length_2 + alarm_length_3)*60 if complete_at_start_time else 0 }}"
+      offset: "{{ calculated_runtime }}"
 condition:
   - condition: state
     entity_id: !input workday_sensor