diff --git a/app/models/metadata_array.rb b/app/models/metadata_array.rb
index 343081c..3e84a8a 100644
--- a/app/models/metadata_array.rb
+++ b/app/models/metadata_array.rb
@@ -7,10 +7,6 @@ class MetadataArray < MetadataTemplate
     []
   end
 
-  def to_param
-    { name => [] }
-  end
-
   private
 
   def sanitize(values)
diff --git a/app/models/metadata_belongs_to.rb b/app/models/metadata_belongs_to.rb
index b2d0ef7..b94fbc2 100644
--- a/app/models/metadata_belongs_to.rb
+++ b/app/models/metadata_belongs_to.rb
@@ -13,11 +13,6 @@ class MetadataBelongsTo < MetadataRelatedPosts
     ''
   end
 
-  # @see MetadataTemplate
-  def to_param
-    name
-  end
-
   def validate
     super
 
diff --git a/app/models/metadata_document_date.rb b/app/models/metadata_document_date.rb
index f49aaa7..036877a 100644
--- a/app/models/metadata_document_date.rb
+++ b/app/models/metadata_document_date.rb
@@ -10,11 +10,9 @@ class MetadataDocumentDate < MetadataTemplate
   # El valor puede ser un Date, Time o una String en el formato
   # "yyyy-mm-dd"
   def value
-    return self[:value] = document.date || default_value if self[:value].nil?
+    return (self[:value] = document.date || default_value) if self[:value].nil?
 
-    if self[:value].is_a? String
-      self[:value] = Date.iso8601(self[:value]).to_time
-    end
+    self[:value] = Date.iso8601(self[:value]).to_time if self[:value].is_a? String
 
     self[:value]
   end
diff --git a/app/models/metadata_file.rb b/app/models/metadata_file.rb
index bb7ce84..0b50523 100644
--- a/app/models/metadata_file.rb
+++ b/app/models/metadata_file.rb
@@ -50,10 +50,6 @@ class MetadataFile < MetadataTemplate
     true
   end
 
-  def to_param
-    { name => %i[description path] }
-  end
-
   # Almacena el archivo en el sitio y lo devuelve
   #
   # @return ActiveStorage::Attachment
diff --git a/app/models/metadata_geo.rb b/app/models/metadata_geo.rb
index 17fb971..1fb3feb 100644
--- a/app/models/metadata_geo.rb
+++ b/app/models/metadata_geo.rb
@@ -10,10 +10,6 @@ class MetadataGeo < MetadataTemplate
     value == default_value
   end
 
-  def to_param
-    { name => %i[lat lng] }
-  end
-
   def save
     return true if empty?
 
diff --git a/app/models/metadata_lang.rb b/app/models/metadata_lang.rb
index 96ba23c..f4a6640 100644
--- a/app/models/metadata_lang.rb
+++ b/app/models/metadata_lang.rb
@@ -7,7 +7,7 @@ class MetadataLang < MetadataTemplate
   end
 
   def value
-    self[:value] || document.collection.label || default_value
+    self[:value] ||= document.collection.label || default_value
   end
 
   def values
diff --git a/app/models/metadata_locales.rb b/app/models/metadata_locales.rb
index 5843b04..6498ed7 100644
--- a/app/models/metadata_locales.rb
+++ b/app/models/metadata_locales.rb
@@ -9,6 +9,7 @@ class MetadataLocales < MetadataTemplate
   # Todos los valores posibles para cada idioma disponible
   #
   # TODO: Optimizar?
+  # TODO: Mantener sincronizados
   #
   # @return { lang: { title: uuid } }
   def values
@@ -20,8 +21,4 @@ class MetadataLocales < MetadataTemplate
       }
     end.inject(:merge)
   end
-
-  def to_param
-    { name => [] }
-  end
 end
diff --git a/app/models/metadata_slug.rb b/app/models/metadata_slug.rb
index ea58c8d..f11fb29 100644
--- a/app/models/metadata_slug.rb
+++ b/app/models/metadata_slug.rb
@@ -33,7 +33,7 @@ class MetadataSlug < MetadataTemplate
   end
 
   def value
-    self[:value] || document.data.fetch('slug', default_value)
+    self[:value] ||= document.data.fetch('slug', default_value)
   end
 
   private
diff --git a/app/models/metadata_template.rb b/app/models/metadata_template.rb
index 8c016b1..80c99e4 100644
--- a/app/models/metadata_template.rb
+++ b/app/models/metadata_template.rb
@@ -53,8 +53,16 @@ MetadataTemplate = Struct.new(:site, :document, :name, :label, :type,
     errors.empty?
   end
 
+  # Usa el valor por defecto para generar el formato de StrongParam
+  # necesario.
+  #
+  # @return [Symbol,Hash]
   def to_param
-    name
+    case default_value
+    when Hash then { name => default_value.keys.map(&:to_sym) }
+    when Array then { name => [] }
+    else name
+    end
   end
 
   def to_s