diff --git a/app/models/billing/page_unlock_promo_code.rb b/app/models/billing/page_unlock_promo_code.rb
index 81b37552..c5d15779 100644
--- a/app/models/billing/page_unlock_promo_code.rb
+++ b/app/models/billing/page_unlock_promo_code.rb
@@ -2,8 +2,10 @@ class PageUnlockPromoCode < ApplicationRecord
   has_many :promotions
   has_many :users, -> { distinct }, through: :promotions
 
-  def unlocked_page_types
-    page_types.split('|') & Rails.application.config.content_types[:all].map(&:name)
+  serialize :page_types, Array
+
+  def whitelisted_page_types
+    page_types & Rails.application.config.content_types[:all].map(&:name)
   end
 
 
@@ -19,7 +21,7 @@ class PageUnlockPromoCode < ApplicationRecord
     # 1 use left, but this seems not worth it to fix
     update(uses_remaining: uses_remaining - 1)
   
-    unlocked_page_types.each do |page_type|
+    whitelisted_page_types.each do |page_type|
       promotions.create(
         user:         user,
         content_type: page_type,