diff --git a/src/atomics_cobalt_parser.c b/src/atomics_cobalt_parser.c
index ace7b7a..545b500 100644
--- a/src/atomics_cobalt_parser.c
+++ b/src/atomics_cobalt_parser.c
@@ -75,7 +75,7 @@ atomics_cobalt_parser_create (dc_parser_t **out, dc_context_t *context)
 	}
 
 	// Set the default values.
-	parser->hydrostatic = 1025.0 * GRAVITY;
+	parser->hydrostatic = DEF_DENSITY_SALT * GRAVITY;
 
 	*out = (dc_parser_t*) parser;
 
diff --git a/src/parser-private.h b/src/parser-private.h
index eed9d51..497b1b1 100644
--- a/src/parser-private.h
+++ b/src/parser-private.h
@@ -25,6 +25,10 @@
 #include <libdivecomputer/context.h>
 #include <libdivecomputer/parser.h>
 
+#define DEF_DENSITY_FRESH 1000.0
+#define DEF_DENSITY_SALT  1025.0
+#define DEF_ATMOSPHERIC   ATM
+
 #ifdef __cplusplus
 extern "C" {
 #endif /* __cplusplus */
diff --git a/src/reefnet_sensus_parser.c b/src/reefnet_sensus_parser.c
index 35fb952..5b3cf7b 100644
--- a/src/reefnet_sensus_parser.c
+++ b/src/reefnet_sensus_parser.c
@@ -80,8 +80,8 @@ reefnet_sensus_parser_create (dc_parser_t **out, dc_context_t *context, unsigned
 	}
 
 	// Set the default values.
-	parser->atmospheric = ATM;
-	parser->hydrostatic = 1025.0 * GRAVITY;
+	parser->atmospheric = DEF_ATMOSPHERIC;
+	parser->hydrostatic = DEF_DENSITY_SALT * GRAVITY;
 	parser->devtime = devtime;
 	parser->systime = systime;
 	parser->cached = 0;
diff --git a/src/reefnet_sensuspro_parser.c b/src/reefnet_sensuspro_parser.c
index c303ee9..267c99e 100644
--- a/src/reefnet_sensuspro_parser.c
+++ b/src/reefnet_sensuspro_parser.c
@@ -79,8 +79,8 @@ reefnet_sensuspro_parser_create (dc_parser_t **out, dc_context_t *context, unsig
 	}
 
 	// Set the default values.
-	parser->atmospheric = ATM;
-	parser->hydrostatic = 1025.0 * GRAVITY;
+	parser->atmospheric = DEF_ATMOSPHERIC;
+	parser->hydrostatic = DEF_DENSITY_SALT * GRAVITY;
 	parser->devtime = devtime;
 	parser->systime = systime;
 	parser->cached = 0;
diff --git a/src/reefnet_sensusultra_parser.c b/src/reefnet_sensusultra_parser.c
index bad5450..da86180 100644
--- a/src/reefnet_sensusultra_parser.c
+++ b/src/reefnet_sensusultra_parser.c
@@ -79,8 +79,8 @@ reefnet_sensusultra_parser_create (dc_parser_t **out, dc_context_t *context, uns
 	}
 
 	// Set the default values.
-	parser->atmospheric = ATM;
-	parser->hydrostatic = 1025.0 * GRAVITY;
+	parser->atmospheric = DEF_ATMOSPHERIC;
+	parser->hydrostatic = DEF_DENSITY_SALT * GRAVITY;
 	parser->devtime = devtime;
 	parser->systime = systime;
 	parser->cached = 0;
diff --git a/src/shearwater_predator_parser.c b/src/shearwater_predator_parser.c
index 5113f75..e1334d7 100644
--- a/src/shearwater_predator_parser.c
+++ b/src/shearwater_predator_parser.c
@@ -245,8 +245,8 @@ shearwater_common_parser_create (dc_parser_t **out, dc_context_t *context, unsig
 	}
 	parser->divemode = M_OC_TEC;
 	parser->units = METRIC;
-	parser->density = 1025;
-	parser->atmospheric = ATM / (BAR / 1000);
+	parser->density = DEF_DENSITY_SALT;
+	parser->atmospheric = DEF_ATMOSPHERIC / (BAR / 1000);
 
 	*out = (dc_parser_t *) parser;
 
@@ -307,8 +307,8 @@ shearwater_predator_parser_set_data (dc_parser_t *abstract, const unsigned char
 	}
 	parser->divemode = M_OC_TEC;
 	parser->units = METRIC;
-	parser->density = 1025;
-	parser->atmospheric = ATM / (BAR / 1000);
+	parser->density = DEF_DENSITY_SALT;
+	parser->atmospheric = DEF_ATMOSPHERIC / (BAR / 1000);
 
 	return DC_STATUS_SUCCESS;
 }