diff --git a/main.py b/main.py
index 94edd16..b28f71c 100644
--- a/main.py
+++ b/main.py
@@ -108,9 +108,10 @@ def format_PU_data(data):
     }
 
 def format_DS_data(data):
+    q_conso = max(np.round(data.get("Inlet_flow", 0.0), 1) - np.round(data.get("Outlet_flow", 0.0), 1),0)
     return {
         "timestamp": datetime.datetime.now().isoformat(),
-        "Qconso": np.round(data.get("Inlet_flow", 0.0), 1) - np.round(data.get("Outlet_flow", 0.0), 1),
+        "Qconso": q_conso ,
         "TankLevel": np.round(data.get("TankLevel", 0.0), 2),
         "Qinlet": np.round(data.get("Inlet_flow", 0.0), 1),
         "Qoutlet": np.round(data.get("Outlet_flow", 0.0), 1),