Index: sansmodels/src/sans/models/c_models/CBinaryHSModel.cpp
===================================================================
--- sansmodels/src/sans/models/c_models/CBinaryHSModel.cpp	(revision f9bf66165686c721c2f0b3a197f7dda1822721ad)
+++ sansmodels/src/sans/models/c_models/CBinaryHSModel.cpp	(revision 27972c1dfdd57a50946a99914051e1713c997e78)
@@ -86,12 +86,8 @@
         
         // Initialize parameter dictionary
+        PyDict_SetItemString(self->params,"s_radius",Py_BuildValue("d",25.000000));
+        PyDict_SetItemString(self->params,"vol_frac_ss",Py_BuildValue("d",0.200000));
+        PyDict_SetItemString(self->params,"l_radius",Py_BuildValue("d",100.000000));
         PyDict_SetItemString(self->params,"vol_frac_ls",Py_BuildValue("d",0.100000));
-        PyDict_SetItemString(self->params,"background",Py_BuildValue("d",0.001000));
-        PyDict_SetItemString(self->params,"vol_frac_ss",Py_BuildValue("d",0.200000));
-        PyDict_SetItemString(self->params,"solvent_sld",Py_BuildValue("d",0.000006));
-        PyDict_SetItemString(self->params,"ls_sld",Py_BuildValue("d",0.000003));
-        PyDict_SetItemString(self->params,"ss_sld",Py_BuildValue("d",0.000000));
-        PyDict_SetItemString(self->params,"s_radius",Py_BuildValue("d",25.000000));
-        PyDict_SetItemString(self->params,"l_radius",Py_BuildValue("d",100.000000));
         // Initialize dispersion / averaging parameter dict
         DispersionVisitor* visitor = new DispersionVisitor();
@@ -234,12 +230,8 @@
 	
 	    // Reader parameter dictionary
+    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
+    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
+    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     self->model->vol_frac_ls = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ls") );
-    self->model->background = PyFloat_AsDouble( PyDict_GetItemString(self->params, "background") );
-    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
-    self->model->solvent_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "solvent_sld") );
-    self->model->ls_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ls_sld") );
-    self->model->ss_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ss_sld") );
-    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
-    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     // Read in dispersion parameters
     PyObject* disp_dict;
@@ -311,12 +303,8 @@
 	
 	    // Reader parameter dictionary
+    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
+    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
+    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     self->model->vol_frac_ls = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ls") );
-    self->model->background = PyFloat_AsDouble( PyDict_GetItemString(self->params, "background") );
-    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
-    self->model->solvent_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "solvent_sld") );
-    self->model->ls_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ls_sld") );
-    self->model->ss_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ss_sld") );
-    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
-    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     // Read in dispersion parameters
     PyObject* disp_dict;
@@ -375,12 +363,8 @@
 	
 	    // Reader parameter dictionary
+    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
+    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
+    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     self->model->vol_frac_ls = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ls") );
-    self->model->background = PyFloat_AsDouble( PyDict_GetItemString(self->params, "background") );
-    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
-    self->model->solvent_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "solvent_sld") );
-    self->model->ls_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ls_sld") );
-    self->model->ss_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ss_sld") );
-    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
-    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     // Read in dispersion parameters
     PyObject* disp_dict;
@@ -408,12 +392,8 @@
 	
 	    // Reader parameter dictionary
+    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
+    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
+    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     self->model->vol_frac_ls = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ls") );
-    self->model->background = PyFloat_AsDouble( PyDict_GetItemString(self->params, "background") );
-    self->model->vol_frac_ss = PyFloat_AsDouble( PyDict_GetItemString(self->params, "vol_frac_ss") );
-    self->model->solvent_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "solvent_sld") );
-    self->model->ls_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ls_sld") );
-    self->model->ss_sld = PyFloat_AsDouble( PyDict_GetItemString(self->params, "ss_sld") );
-    self->model->s_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "s_radius") );
-    self->model->l_radius = PyFloat_AsDouble( PyDict_GetItemString(self->params, "l_radius") );
     // Read in dispersion parameters
     PyObject* disp_dict;
