diff --git a/server/models/AlertLog.js b/server/models/AlertLog.js
index 492ae3f..d588bec 100644
--- a/server/models/AlertLog.js
+++ b/server/models/AlertLog.js
@@ -85,11 +85,11 @@ module.exports = (sequelize) => {
     },
     created_at: {
       type: DataTypes.DATE,
-      defaultValue: DataTypes.NOW
+      defaultValue: sequelize.Sequelize.NOW
     },
     updated_at: {
       type: DataTypes.DATE,
-      defaultValue: DataTypes.NOW
+      defaultValue: sequelize.Sequelize.NOW
     }
   }, {
     tableName: 'alert_logs',
diff --git a/server/models/DroneDetection.js b/server/models/DroneDetection.js
index 4d6f05d..3427467 100644
--- a/server/models/DroneDetection.js
+++ b/server/models/DroneDetection.js
@@ -57,7 +57,7 @@ module.exports = (sequelize) => {
     },
     server_timestamp: {
       type: DataTypes.DATE,
-      defaultValue: DataTypes.NOW,
+      defaultValue: sequelize.Sequelize.NOW,
       comment: 'When the detection was received by server'
     },
     confidence_level: {
@@ -100,7 +100,7 @@ module.exports = (sequelize) => {
     },
     created_at: {
       type: DataTypes.DATE,
-      defaultValue: DataTypes.NOW
+      defaultValue: sequelize.Sequelize.NOW
     }
   }, {
     tableName: 'drone_detections',
diff --git a/server/tests/models/models.test.js b/server/tests/models/models.test.js
index feee9e1..69aedfb 100644
--- a/server/tests/models/models.test.js
+++ b/server/tests/models/models.test.js
@@ -554,9 +554,16 @@ describe('Models', () => {
 
   describe('Heartbeat Model', () => {
     it('should create heartbeat with valid data', async () => {
+      const tenant = await createTestTenant();
+      const device = await models.Device.create({
+        id: 123,
+        name: 'Test Device',
+        tenant_id: tenant.id
+      });
+
       const heartbeatData = {
         key: 'device_123_key',
-        device_id: 123,
+        device_id: device.id,
         signal_strength: -50,
         battery_level: 85,
         temperature: 22.5
@@ -566,18 +573,25 @@ describe('Models', () => {
 
       expect(heartbeat.id).to.exist;
       expect(heartbeat.key).to.equal('device_123_key');
-      expect(heartbeat.device_id).to.equal(123);
+      expect(heartbeat.device_id).to.equal(device.id);
       expect(heartbeat.battery_level).to.equal(85);
     });
 
     it('should auto-set timestamp', async () => {
-      const heartbeat = await models.Heartbeat.create({
-        key: 'device_123_key',
-        device_id: 123
+      const tenant = await createTestTenant();
+      const device = await models.Device.create({
+        id: 124,
+        name: 'Test Device 2',
+        tenant_id: tenant.id
       });
 
-      expect(heartbeat.timestamp).to.exist;
-      expect(heartbeat.timestamp).to.be.a('date');
+      const heartbeat = await models.Heartbeat.create({
+        key: 'device_124_key',
+        device_id: device.id
+      });
+
+      expect(heartbeat.created_at).to.exist;
+      expect(heartbeat.created_at).to.be.a('date');
     });
 
     it('should validate battery level range', async () => {