diff --git a/tmpl/alert-rules.yml b/tmpl/alert-rules.yml
index 2eb4b80..8c6a684 100644
--- a/tmpl/alert-rules.yml
+++ b/tmpl/alert-rules.yml
@@ -33,7 +33,7 @@ groups:
   # Heavy "/" use
   - alert: filesystem_threshold_exceeded
     expr: node_filesystem_avail{job="%%{job_name_node}",mountpoint="/"} / node_filesystem_size{job="%%{job_name_node}"}
-      * 100 < 90
+      * 100 < 20
     annotations:
       description: This device's filesystem usage has exceeded the threshold with
         a value of {{ $value }}.