diff --git a/objectifier-module.nix b/objectifier-module.nix
index f77f159..62c72af 100644
--- a/objectifier-module.nix
+++ b/objectifier-module.nix
@@ -44,7 +44,7 @@ in {
         default = (60 * 60 * 8); # 8 hours
       };
 
-      delay = {
+      delay = mkOption {
         type = int;
         description = "Time between cleanup sweeps.";
         default = (60 * 10); # 10 minutes