diff --git a/advanced-reactor.html b/advanced-reactor.html
index eade6d7..f6bedc9 100644
--- a/advanced-reactor.html
+++ b/advanced-reactor.html
@@ -3,7 +3,7 @@
         category: 'WWTP',
         color: '#c4cce0',
         defaults: {
-            name: {value:""}
+            name: { value: "" },
         },
         inputs: 1,
         outputs: 1,
diff --git a/advanced-reactor.js b/advanced-reactor.js
index e9d7107..1cd3e21 100644
--- a/advanced-reactor.js
+++ b/advanced-reactor.js
@@ -5,9 +5,18 @@ module.exports = function(RED) {
 
         let name = config.name;
 
-        node.on('input', function(msg) {
-            msg.payload = msg.payload.toLowerCase();
-            node.send(msg);
+        const Reactor = require('./dependencies/reactor_class');
+
+        const reactor = new Reactor(Array(13).fill(0.001));
+
+        node.on('input', function(msg, send, done) {
+            if (msg.topic == "clock") {
+                reactor.updateState(msg);
+            }
+
+            if (done) {
+                done();
+            }
         });
     }
     RED.nodes.registerType("advanced-reactor", reactor);
diff --git a/dependencies/asm3_class.js b/dependencies/asm3_class.js
index b5c795e..9ad03d9 100644
--- a/dependencies/asm3_class.js
+++ b/dependencies/asm3_class.js
@@ -117,7 +117,7 @@ class ASM3 {
     rates[9] = mu_A_max * this._monod(S_O, K_A_O) * this._monod(S_NH, K_A_NH) * this._monod(S_HCO, K_A_HCO) * X_A;
     rates[10] = b_A_O * this._monod(S_O, K_O) * X_A;
     rates[11] = b_A_NO * this._inv_monod(S_O, K_A_O) * this._monod(S_NO, K_NO) * X_A;
-
+    
     return rates;
   }
 
diff --git a/dependencies/reactor_class.js b/dependencies/reactor_class.js
index 4db5522..8c69516 100644
--- a/dependencies/reactor_class.js
+++ b/dependencies/reactor_class.js
@@ -5,26 +5,34 @@ class Reactor_CSTR {
     
     constructor(initial_state) {
         this.state = initial_state;
+        console.log(this.state);
         this.asm = new ASM3();
 
         this.Vl = 10.0; // fluid volume reactor [m3]
         this.F = 1.0; // fluid debit [m3 d-1]
-        this.C_in = Array(13).fill(0.0); // composition influent
+        this.C_in = [0., 30., 100., 16., 0., 0., 5., 25., 75., 30., 0., 0., 125.]; // composition influent
         this.OTR = 100.0; // oxygen transfer rate [g O2 d-1]
 
         this.currentTime = Date.now(); // milliseconds since epoch [ms]
-        this.timeStep = 1/(24*60) // time step [d]
+        this.timeStep = 1/(24*60*15) // time step [d]
     }
 
     // expect update with timestamp
     updateState(input) {
-        throw new Error("Not implemented yet");
-
         let newTime = input.payload;
 
         const day2ms = 1000 * 60 * 60 * 24; 
 
-        let n_iter = (newTime - this.currentTime) % (this.timeStep * day2ms);
+        let n_iter = Math.floor((newTime - this.currentTime) / (this.timeStep * day2ms));
+        if (n_iter > 0) {
+            let n = 0;
+            while (n < n_iter) {
+                console.log(this.tick_fe(this.timeStep));
+                n += 1;
+            }
+            this.currentTime += n_iter * this.timeStep * day2ms;
+            n_iter = 0;
+        }
     }
 
     tick_fe(time_step) { // tick reactor state using forward Euler method
@@ -43,11 +51,13 @@ class Reactor_CSTR {
 
 // testing stuff
 // state: S_O, S_I, S_S, S_NH, S_N2, S_NO, S_HCO, X_I, X_S, X_H, X_STO, X_A, X_TS
-let initial_state = [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1];
-const Reactor = new Reactor_CSTR(initial_state);
-Reactor.C_in = [0.0, 30., 100., 16., 0., 0., 5., 25., 75., 30., 0., 0., 125.];
-N = 0;
-while (N < 500) {
-    console.log(Reactor.tick_fe(0.001));
-    N += 1;
-}
\ No newline at end of file
+// let initial_state = [0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1, 0.1];
+// const Reactor = new Reactor_CSTR(initial_state);
+// Reactor.C_in = [0.0, 30., 100., 16., 0., 0., 5., 25., 75., 30., 0., 0., 125.];
+// N = 0;
+// while (N < 500) {
+//     console.log(Reactor.tick_fe(0.001));
+//     N += 1;
+// }
+
+module.exports = Reactor_CSTR;
\ No newline at end of file