diff --git a/include/cantera/zeroD/ReactorNet.h b/include/cantera/zeroD/ReactorNet.h
index ffb1dfcad..c849deaaa 100644
--- a/include/cantera/zeroD/ReactorNet.h
+++ b/include/cantera/zeroD/ReactorNet.h
@@ -79,11 +79,6 @@ public:
         return m_atols;
     }
 
-    /**
-     * Initialize the reactor network.
-     */
-    void initialize(doublereal t0 = 0.0);
-
     /**
      * Advance the state of all reactors in time.
      * @param time Time to advance to (s).
@@ -152,6 +147,11 @@ public:
     }
 
 protected:
+    /**
+     * Initialize the reactor network. Called automatically the first time
+     * advance or step is called.
+     */
+    void initialize();
 
     std::vector<ReactorBase*> m_r;
     std::vector<Reactor*> m_reactors;
diff --git a/src/zeroD/ReactorNet.cpp b/src/zeroD/ReactorNet.cpp
index ea309d55f..5bdf19730 100644
--- a/src/zeroD/ReactorNet.cpp
+++ b/src/zeroD/ReactorNet.cpp
@@ -44,7 +44,7 @@ ReactorNet::~ReactorNet()
     deleteIntegrator(m_integ);
 }
 
-void ReactorNet::initialize(doublereal t0)
+void ReactorNet::initialize()
 {
     size_t n, nv;
     char buf[100];
@@ -59,7 +59,7 @@ void ReactorNet::initialize(doublereal t0)
                            "no reactors in network!");
     for (n = 0; n < m_nr; n++) {
         if (m_r[n]->type() >= ReactorType) {
-            m_r[n]->initialize(t0);
+            m_r[n]->initialize(m_time);
             Reactor* r = (Reactor*)m_r[n];
             m_reactors.push_back(r);
             nv = r->neq();
@@ -132,7 +132,7 @@ void ReactorNet::initialize(doublereal t0)
         sprintf(buf, "Maximum time step:   %14.6g\n", m_maxstep);
         writelog(buf);
     }
-    m_integ->initialize(t0, *this);
+    m_integ->initialize(m_time, *this);
     m_init = true;
 }