diff --git a/src/pg.ml b/src/pg.ml
index 216f2551..a8f28e73 100644
--- a/src/pg.ml
+++ b/src/pg.ml
@@ -7,7 +7,10 @@
    GNU Taler db-events?
    it seems caqti/pgx does not support it *)
 
+module type CONN = Caqti_miou.CONNECTION
+
 open Crypto
+open Bin_type
 
 module Caqti_type = struct
   include Caqti_type
@@ -31,7 +34,6 @@ module Caqti_type = struct
 
   include struct
     (* alias for hash *)
-    open Bin_type
 
     let fullpayto_hash = FullPaytoHash.caqti
     let nomalizaedpayto_hash = NormalizedPaytoHash.caqti
@@ -49,10 +51,6 @@ module Caqti_type = struct
   include Caqti_request.Infix
 end
 
-module type CONN = Caqti_miou.CONNECTION
-
-open Bin_type
-
 let preflight =
   let l =
     List.map