diff --git a/src/hydro/PressureEnergy/hydro_iact.h b/src/hydro/PressureEnergy/hydro_iact.h
index 65c46a55554d4a8f09b32bb6eb1deb1fdcfc932a..e23b06247e255bee088bd920dee46919443abd96 100644
--- a/src/hydro/PressureEnergy/hydro_iact.h
+++ b/src/hydro/PressureEnergy/hydro_iact.h
@@ -232,10 +232,13 @@ __attribute__((always_inline)) INLINE static void runner_iact_force(
   /* Compute dv dot r. */
   const float dvdr = (pi->v[0] - pj->v[0]) * dx[0] +
                      (pi->v[1] - pj->v[1]) * dx[1] +
-                     (pi->v[2] - pj->v[2]) * dx[2] + a2_Hubble * r2;
+                     (pi->v[2] - pj->v[2]) * dx[2];
+
+  /* Includes the hubble flow term; not used for du/dt */
+  const float dvdr_Hubble = dvdr + a2_Hubble * r2;
 
   /* Are the part*icles moving towards each others ? */
-  const float omega_ij = min(dvdr, 0.f);
+  const float omega_ij = min(dvdr_Hubble, 0.f);
   const float mu_ij = fac_mu * r_inv * omega_ij; /* This is 0 or negative */
 
   /* Compute sound speeds and signal velocity */
@@ -357,10 +360,13 @@ __attribute__((always_inline)) INLINE static void runner_iact_nonsym_force(
   /* Compute dv dot r. */
   const float dvdr = (pi->v[0] - pj->v[0]) * dx[0] +
                      (pi->v[1] - pj->v[1]) * dx[1] +
-                     (pi->v[2] - pj->v[2]) * dx[2] + a2_Hubble * r2;
+                     (pi->v[2] - pj->v[2]) * dx[2];
+
+  /* Includes the hubble flow term; not used for du/dt */
+  const float dvdr_Hubble = dvdr + a2_Hubble * r2;
 
   /* Are the part*icles moving towards each others ? */
-  const float omega_ij = min(dvdr, 0.f);
+  const float omega_ij = min(dvdr_Hubble, 0.f);
   const float mu_ij = fac_mu * r_inv * omega_ij; /* This is 0 or negative */
 
   /* Compute sound speeds and signal velocity */