diff --git a/src/debug.c b/src/debug.c
index e7b60c52f92fdb64fdefc8ac5c5e353f1ab57e6e..487fd53e74399ef7bd1802704adbf84bbc3dc0a3 100644
--- a/src/debug.c
+++ b/src/debug.c
@@ -32,6 +32,7 @@
 /* Local includes. */
 #include "config.h"
 #include "const.h"
+#include "hydro.h"
 #include "inline.h"
 #include "part.h"
 
diff --git a/src/hydro/Gadget2/hydro_part.h b/src/hydro/Gadget2/hydro_part.h
index 02fd1bddcef97c336e88935f6e712e518081fa31..b2e5e53094525efe19f8b139f4d46ce48e9bb9cd 100644
--- a/src/hydro/Gadget2/hydro_part.h
+++ b/src/hydro/Gadget2/hydro_part.h
@@ -55,56 +55,52 @@ struct part {
   /* Particle density. */
   float rho;
 
-  /* Derivative of the density with respect to this particle's smoothing length.
-   */
-  float rho_dh;
-
   /* Particle entropy. */
   float entropy;
 
-  /* Derivative of the density with respect to  smoothing length. */
+  /* Derivative of the density with respect to smoothing length. */
   float rho_dh;
 
-  union {
+  // union {
 
-    struct {
+  struct {
 
-      /* Number of neighbours. */
-      float wcount;
+    /* Number of neighbours. */
+    float wcount;
 
-      /* Number of neighbours spatial derivative. */
-      float wcount_dh;
+    /* Number of neighbours spatial derivative. */
+    float wcount_dh;
 
-      /* Particle velocity curl. */
-      float rot_v[3];
+    /* Particle velocity curl. */
+    float rot_v[3];
 
-      /* Particle velocity divergence. */
-      float div_v;
+    /* Particle velocity divergence. */
+    float div_v;
 
-    } density;
+  } density;
 
-    struct {
+  struct {
 
-      /* Balsara switch */
-      float balsara;
+    /* Balsara switch */
+    float balsara;
 
-      /* Pressure over density squared (including drho/dh term) */
-      float P_over_rho2;
+    /* Pressure over density squared (including drho/dh term) */
+    float P_over_rho2;
 
-      /* Particle sound speed. */
-      float soundspeed;
+    /* Particle sound speed. */
+    float soundspeed;
 
-      /* Signal velocity. */
-      float v_sig;
+    /* Signal velocity. */
+    float v_sig;
 
-      /* Entropy time derivative */
-      float entropy_dt;
+    /* Entropy time derivative */
+    float entropy_dt;
 
-      /* Time derivative of the smoothing length */
-      float h_dt;
+    /* Time derivative of the smoothing length */
+    float h_dt;
 
-    } force;
-  };
+  } force;
+  //  };
 
   /* Particle ID. */
   long long id;