diff --git a/src/specificClass.js b/src/specificClass.js
index 6378307..ead9800 100644
--- a/src/specificClass.js
+++ b/src/specificClass.js
@@ -228,6 +228,10 @@ class Reactor {
       }
       this.currentTime += n_iter * this.timeStep * DAY2MS / this.speedUpFactor;
       this.emitter.emit("stateChange", this.currentTime);
+
+      if (this.returnPump) {
+        this.returnPump.updateSourceSink();
+      }
     }
   }
 }