diff --git a/src/obiavl.c b/src/obiavl.c
index 69f2a3e..c96e24b 100644
--- a/src/obiavl.c
+++ b/src/obiavl.c
@@ -1273,7 +1273,7 @@ OBIDMS_avl_p obi_create_avl(OBIDMS_p dms, const char* avl_name)
 	avl->data_fd = avl_data_file_descriptor;
 
 	// Bloom filter
-	bloom_init(&((avl->header)->bloom_filter), 2000000, 0.001);	// TODO use macros
+	bloom_init(&((avl->header)->bloom_filter), NODE_COUNT_PER_AVL, BLOOM_FILTER_ERROR_RATE);
 
 	//close(avl_file_descriptor);
 
@@ -1575,7 +1575,7 @@ index_t insert_in_avl_group(OBIDMS_avl_group_p avl_group, byte_t* value)	// TODO
 
 	// not found in any avl: add in current
 	// first, check if make new one
-	if ((((avl_group->sub_avls)[avl_group->current_avl_idx])->header)->nb_items == 2000000)		// TODO add condition with data size + use macro
+	if ((((avl_group->sub_avls)[avl_group->current_avl_idx])->header)->nb_items == NODE_COUNT_PER_AVL)		// TODO add condition with data size
 		obi_add_new_avl_in_group(avl_group);
 
 	bloom_add(&((((avl_group->sub_avls)[avl_group->current_avl_idx])->header)->bloom_filter), value, (BYTE_ARRAY_HEADER_SIZE + *((int32_t*)(value+1))));
diff --git a/src/obiavl.h b/src/obiavl.h
index 1850455..cfe1c5f 100644
--- a/src/obiavl.h
+++ b/src/obiavl.h
@@ -27,8 +27,9 @@
 
 #include "bloom.h"
 
-#define NB_OF_AVLS (64)
-#define MASK (63)
+#define NODE_COUNT_PER_AVL (2000000)
+
+#define BLOOM_FILTER_ERROR_RATE (0.001)
 
 #define AVL_MAX_NAME (1024) 								/**< The maximum length of an AVL tree name.
                               	  	 	 	 	 	 	 	 */