diff --git a/gui/main.py b/gui/main.py
index df67f9f..30d3ff4 100644
--- a/gui/main.py
+++ b/gui/main.py
@@ -3,7 +3,7 @@ import serial
 import serial.tools.list_ports
 from PyQt6.QtWidgets import (QApplication, QMainWindow, QVBoxLayout, QHBoxLayout, 
                             QWidget, QLabel, QPushButton, QComboBox, QDoubleSpinBox,
-                            QGroupBox, QStatusBar, QMessageBox)
+                            QGroupBox, QStatusBar, QMessageBox, QCheckBox)
 from PyQt6.QtCore import QTimer, Qt
 from PyQt6.QtGui import QFont
 
@@ -74,8 +74,13 @@ class PHControllerGUI(QMainWindow):
         self.pump_off_btn = QPushButton("Pumpe Aus")
         self.pump_off_btn.clicked.connect(lambda: self.send_pump_command(0))
         
+        # Volume reset option
+        self.reset_volume_checkbox = QCheckBox("Volumen bei Start zurücksetzen")
+        self.reset_volume_checkbox.setChecked(True)  # Default: reset volume
+        
         pump_control_layout.addWidget(self.pump_on_btn)
         pump_control_layout.addWidget(self.pump_off_btn)
+        pump_control_layout.addWidget(self.reset_volume_checkbox)
         
         # Tube Selection
         tube_layout = QHBoxLayout()
@@ -228,6 +233,7 @@ class PHControllerGUI(QMainWindow):
         self.cal_ph7_btn.setEnabled(enabled)
         self.auto_dose_btn.setEnabled(enabled)
         self.volume_spin.setEnabled(enabled)
+        self.reset_volume_checkbox.setEnabled(enabled)
     
     def send_command(self, command):
         print(command)
@@ -275,9 +281,14 @@ class PHControllerGUI(QMainWindow):
             self.flow_rate_label.setVisible(True)
             self.total_volume_label.setVisible(True)
             
-            # Reset volume counter and start timing
-            self.total_volume = 0.0
-            self.total_volume_label.setText("Gesamt: 0.0 ml")
+            # Check if volume should be reset or continue accumulating
+            if self.reset_volume_checkbox.isChecked():
+                # Reset volume counter
+                self.total_volume = 0.0
+                self.total_volume_label.setText("Gesamt: 0.0 ml")
+            else:
+                # Continue with existing volume - just update display
+                self.total_volume_label.setText(f"Gesamt: {self.total_volume:.2f} ml")
             
             self.flow_rate_timer.start(1000)  # Request flow rate every second
         else: