diff --git a/lib/classes/sphinx/configuration.class.php b/lib/classes/sphinx/configuration.class.php
index e6c7df30ad..cbd3b40972 100644
--- a/lib/classes/sphinx/configuration.class.php
+++ b/lib/classes/sphinx/configuration.class.php
@@ -67,15 +67,17 @@ class sphinx_configuration
 
     $defaults = array(
         'sbas' => self::OPT_ALL_SBAS
-        , 'libstemmer' => array(self::OPT_LIBSTEMMER_NONE)
+      , 'libstemmer' => array(self::OPT_LIBSTEMMER_NONE)
         , 'enable_star' => self::OPT_ENABLE_STAR_ON
-        , 'min_prefix_len' => self::OPT_MIN_PREFIX_LEN
+      , 'min_prefix_len' => self::OPT_MIN_PREFIX_LEN
         , 'min_infix_len' => self::OPT_MIN_INFIX_LEN
         , 'charset_tables' => array()
     );
 
     $options = array_merge($defaults, $options);
 
+    $options['charset_tables'] = array_unique($options['charset_tables']);
+
     $lb = phrasea::sbas_params();
 
     $conf = '';
@@ -439,7 +441,7 @@ class sphinx_configuration
     path                  = /var/sphinx/datas/docs_realtime_' . $serialized . '
 
 
-' . $charset_abstract . '
+    ' . $charset_abstract . '
 
     rt_field              = value
 #    rt_field              = meta_struct_id
@@ -593,7 +595,7 @@ searchd
   # optional, default is 256
   #
   max_filters             = 512
-  
+
   compat_sphinxql_magics  = 0
 
 }