diff --git a/app/Admin/Controllers/Activity/IndexController.php b/app/Admin/Controllers/Activity/IndexController.php
index a227959..4c160e5 100644
--- a/app/Admin/Controllers/Activity/IndexController.php
+++ b/app/Admin/Controllers/Activity/IndexController.php
@@ -133,8 +133,13 @@ class IndexController extends AdminController
 
                 return back()->withInput()->with(compact('error'));
             }
-            $form->start_at = $form->start_at . ' 00:00:01';
-            $form->end_at   = $form->end_at . ' 23:59:59';
+            if (request()->start) {
+                $form->start_at = $form->start_at . ' 00:00:01';
+            }
+
+            if (request()->end_at) {
+                $form->end_at = $form->end_at . ' 23:59:59';
+            }
         });
 
         return $form;
diff --git a/app/Models/Log.php b/app/Models/Log.php
index bed92cd..52a631e 100644
--- a/app/Models/Log.php
+++ b/app/Models/Log.php
@@ -9,11 +9,11 @@ use Schema;
 class Log extends Model
 {
 
-    protected $guarded = ['id'];
+    protected $guarded;
 
     protected $table;
 
-    protected $casts   = [
+    protected $casts = [
         'in_source'  => 'array',
         'out_source' => 'array',
     ];