diff --git a/src/controllers/tanksController.js b/src/controllers/tanksController.js
index e4afd07d..69f80fc9 100644
--- a/src/controllers/tanksController.js
+++ b/src/controllers/tanksController.js
@@ -6149,32 +6149,37 @@ async function processIotData(hw_Id, data) {
       console.log(`🚰 Tank [${tankhardwareId}] - Level: ${tankHeight}, Calculated Water Level: ${waterLevel}`);
       if (tankHeight <= 0) {
         const now = moment().tz('Asia/Kolkata');
+        const formattedNow = now.format('DD-MMM-YYYY - HH:mm:ss');
       
-        if (!existingTank.slave_status || existingTank.slave_status !== "not_working") {
+        if (existingTank.slave_status !== "not_working") {
           if (!existingTank.slave_disconnected_time) {
-            // First time signal lost
-            const disconnectedTime = now.format('DD-MMM-YYYY - HH:mm:ss');
+            // First time signal is lost
             existingTank.slave_status = "signal_lost";
-            existingTank.slave_disconnected_time = disconnectedTime;
+            existingTank.slave_disconnected_time = formattedNow;
             await existingTank.save();
-            console.log(`⚠️ Slave signal lost for tank [${tankhardwareId}] at ${disconnectedTime}`);
+            console.log(`⚠️ Slave signal lost for tank [${tankhardwareId}] at ${formattedNow}`);
           } else if (existingTank.slave_status === "signal_lost") {
             const disconnectedMoment = moment(existingTank.slave_disconnected_time, 'DD-MMM-YYYY - HH:mm:ss');
-            const minutesDiff = now.diff(disconnectedMoment, 'minutes');
-            if (minutesDiff >= 5) {
-              existingTank.slave_status = "not_working";
-              await existingTank.save();
-              console.log(`❌ Slave marked as not_working for tank [${tankhardwareId}] after ${minutesDiff} minutes`);
+            if (!disconnectedMoment.isValid()) {
+              console.error(`❌ Invalid slave_disconnected_time format for tank [${tankhardwareId}]`);
             } else {
-              console.log(`⏳ Slave still within grace period (${minutesDiff} min) for tank [${tankhardwareId}]`);
+              const minutesDiff = now.diff(disconnectedMoment, 'minutes');
+              console.log(`⏳ Minutes since disconnect for tank [${tankhardwareId}]: ${minutesDiff} min`);
+      
+              if (minutesDiff >= 5) {
+                existingTank.slave_status = "not_working";
+                await existingTank.save();
+                console.log(`❌ Slave marked as not_working for tank [${tankhardwareId}] after ${minutesDiff} minutes`);
+              } else {
+                console.log(`ℹ️ Still within 5-minute window for tank [${tankhardwareId}], no update yet`);
+              }
             }
           }
         } else {
-          console.log(`⏩ Slave already marked as not_working for tank [${tankhardwareId}], skipping update.`);
+          console.log(`⏩ Slave already marked as not_working for tank [${tankhardwareId}], skipping update`);
         }
       }
       
-      
 
       if (tankHeight > 0 && waterLevel >= 0) {
         existingTank.waterlevel = waterLevel;