diff --git a/app/lib/activity_tracker.rb b/app/lib/activity_tracker.rb
index 50e927b0ce47eb04fb480499a8c6d588d18aa5dc..5b497267477aff862a5e18e759841608f5e82ba2 100644
--- a/app/lib/activity_tracker.rb
+++ b/app/lib/activity_tracker.rb
@@ -15,7 +15,7 @@ class ActivityTracker
       key = [prefix, current_week].join(':')
 
       redis.pfadd(key, value)
-      redis.expire(key, value)
+      redis.expire(key, EXPIRE_AFTER)
     end
 
     private