diff --git a/cpu/Greyscale.cpp b/cpu/Greyscale.cpp
index 5f6d3633..4aab97e2 100644
--- a/cpu/Greyscale.cpp
+++ b/cpu/Greyscale.cpp
@@ -1959,7 +1959,8 @@ extern "C" void ScaLBL_D3Q19_AAodd_Greyscale_MRT(int *neighborList, double *dist
         }
 
         //Calculate pressure for MRT model
-        pressure=rho/3.f/porosity;
+        //pressure=rho/3.f/porosity;
+        pressure=rho/3.f;
 
         //-------------------- MRT collison where body force has NO higher-order terms -------------//
 		m1 = m1 + rlx_setA*((19*(ux*ux+uy*uy+uz*uz)*rho0/porosity - 11*rho) - m1);
@@ -2457,7 +2458,8 @@ extern "C" void ScaLBL_D3Q19_AAeven_Greyscale_MRT(double *dist, int start, int f
         }
 
         //Calculate pressure for Incompressible-MRT model
-        pressure=rho/3.f/porosity;
+        //pressure=rho/3.f/porosity;
+        pressure=rho/3.f;
 
         //-------------------- IMRT collison where body force has NO higher-order terms -------------//
 		m1 = m1 + rlx_setA*((19*(ux*ux+uy*uy+uz*uz)*rho0/porosity - 11*rho) - m1);
diff --git a/gpu/Greyscale.cu b/gpu/Greyscale.cu
index 57452bbb..edf80a16 100644
--- a/gpu/Greyscale.cu
+++ b/gpu/Greyscale.cu
@@ -1990,7 +1990,8 @@ __global__ void dvc_ScaLBL_D3Q19_AAodd_Greyscale_MRT(int *neighborList, double *
             }
 
             //Calculate pressure for MRT model
-            pressure=rho/3.f/porosity;
+            //pressure=rho/3.f/porosity;
+            pressure=rho/3.f;
 
             //-------------------- MRT collison where body force has NO higher-order terms -------------//
 			m1 = m1 + rlx_setA*((19*(ux*ux+uy*uy+uz*uz)*rho0/porosity - 11*rho) - m1);
@@ -2496,7 +2497,8 @@ __global__ void dvc_ScaLBL_D3Q19_AAeven_Greyscale_MRT(double *dist, int start, i
             }
 
             //Calculate pressure for Incompressible-MRT model
-            pressure=rho/3.f/porosity;
+            //pressure=rho/3.f/porosity;
+            pressure=rho/3.f;
 
             //-------------------- IMRT collison where body force has NO higher-order terms -------------//
 			m1 = m1 + rlx_setA*((19*(ux*ux+uy*uy+uz*uz)*rho0/porosity - 11*rho) - m1);
diff --git a/gpu/GreyscaleColor.cu b/gpu/GreyscaleColor.cu
index b3398d32..69c9a080 100644
--- a/gpu/GreyscaleColor.cu
+++ b/gpu/GreyscaleColor.cu
@@ -512,7 +512,8 @@ __global__ void dvc_ScaLBL_D3Q19_AAodd_GreyscaleColor(int *neighborList, int *Ma
 			Velocity[n] = ux;
 			Velocity[Np+n] = uy;
 			Velocity[2*Np+n] = uz;
-            Pressure[n] = rho/3.f/porosity;
+            //Pressure[n] = rho/3.f/porosity;
+            Pressure[n] = rho/3.f;
 
 			//........................................................................
 			//..............carry out relaxation process..............................
@@ -1218,7 +1219,8 @@ __global__  void dvc_ScaLBL_D3Q19_AAeven_GreyscaleColor(int *Map, double *dist,
 			Velocity[n] = ux;
 			Velocity[Np+n] = uy;
 			Velocity[2*Np+n] = uz;
-            Pressure[n] = rho/3.f/porosity;
+            //Pressure[n] = rho/3.f/porosity;
+            Pressure[n] = rho/3.f;
 
 			//........................................................................
 			//..............carry out relaxation process..............................