diff --git a/server.js b/server.js
index a2c78c7..1baae3d 100644
--- a/server.js
+++ b/server.js
@@ -519,10 +519,8 @@ function evaluateAlarms(readings, outputChanges = []) {
 
             // 1. Output State Change Triggers
             if (trigger.outputChange && outputChanges.length > 0) {
-                // config: { target: "Dev:1", toState: "on" }
-                // or "Any"
-                const target = trigger.outputChange.target; // "Dev:1:out" or "any"
-                const curState = trigger.outputChange.state; // "on" or "off"
+                const target = trigger.outputChange.target;
+                const curState = trigger.outputChange.state;
 
                 const match = outputChanges.find(c => {
                     const k = `${c.devName}:${c.port}`;
@@ -534,8 +532,8 @@ function evaluateAlarms(readings, outputChanges = []) {
                 if (match) triggered = true;
             }
 
-            // 2. Sensor Triggers (Existing Logic)
-            let sensorDetails = []; // Track sensor values for logging
+            // 2. Sensor Triggers (with DB fallback for external sensors like CO2)
+            let sensorDetails = [];
             if (!triggered && trigger.sensors && trigger.sensors.length > 0) {
                 const results = trigger.sensors.map(cond => {
                     const sensorId = cond.sensor;
@@ -544,24 +542,38 @@ function evaluateAlarms(readings, outputChanges = []) {
 
                     const parts = sensorId.split(':');
                     const devName = parts[0];
+                    const portNum = parts.length > 1 ? parseInt(parts[1]) : null;
                     const type = parts.length === 2 ? parts[1] : parts[2];
 
-                    const reading = readings.find(r => r.devName === devName);
-                    if (!reading) {
-                        sensorDetails.push({ sensor: sensorId, value: 'NO_READING', operator, threshold });
-                        return false;
-                    }
-
                     let value = null;
-                    if (type === 'temp') value = reading.temp_c;
-                    if (type === 'humidity') value = reading.humidity;
-                    if (type === 'level') {
-                        const portNum = parseInt(parts[1]);
+
+                    // First try live readings from API
+                    const reading = readings.find(r => r.devName === devName);
+
+                    if (type === 'temp' && reading) value = reading.temp_c;
+                    if (type === 'humidity' && reading) value = reading.humidity;
+                    if (type === 'level' && reading && portNum !== null) {
                         const p = reading.ports.find(rp => rp.port === portNum);
                         if (p) value = p.speak;
                     }
 
-                    // Track the sensor value for logging
+                    // Fallback: Query database for recent readings (for external sensors like CO2)
+                    if (value === null && portNum !== null) {
+                        try {
+                            const dbReading = db.prepare(`
+                                SELECT level FROM readings 
+                                WHERE dev_name = ? AND port = ? 
+                                ORDER BY timestamp DESC LIMIT 1
+                            `).get(devName, portNum);
+                            if (dbReading && dbReading.level !== null) {
+                                value = dbReading.level;
+                            }
+                        } catch (e) {
+                            console.error('DB fallback read error:', e);
+                        }
+                    }
+
+                    // Track sensor value for logging
                     sensorDetails.push({ sensor: sensorId, value: value, operator, threshold });
 
                     if (value === null || value === undefined) return false;
@@ -584,16 +596,15 @@ function evaluateAlarms(readings, outputChanges = []) {
             }
 
             if (triggered) {
-                // Build detailed sensor info string
                 const sensorInfo = sensorDetails.map(s =>
-                    `${s.sensor}: ${s.value === null ? 'NULL' : s.value === 'NO_READING' ? 'NO_READING' : s.value} (${s.operator} ${s.threshold})`
+                    `${s.sensor}: ${s.value === null ? 'NULL' : s.value} (${s.operator} ${s.threshold})`
                 ).join(', ');
 
                 console.log(`ALARM TRIGGERED: ${alarm.name} | Sensors: ${sensorInfo}`);
                 alarmStates.set(alarm.id, Date.now());
                 const action = JSON.parse(alarm.action_data);
                 const msg = `🚨 ALARM: ${alarm.name}\n\n${action.message || 'No message'}\n\n📊 Sensor Values:\n${sensorDetails.map(s =>
-                    `• ${s.sensor}: ${s.value === null ? 'NULL' : s.value === 'NO_READING' ? 'NO_READING' : s.value} (threshold: ${s.operator} ${s.threshold})`
+                    `• ${s.sensor}: ${s.value === null ? 'NULL' : s.value} (threshold: ${s.operator} ${s.threshold})`
                 ).join('\n')}`;
                 sendTelegramNotification(msg);
             }
diff --git a/src/client/LevelChart.js b/src/client/LevelChart.js
index d2aef3d..137e785 100644
--- a/src/client/LevelChart.js
+++ b/src/client/LevelChart.js
@@ -56,7 +56,7 @@ export default function LevelChart({ data, isLight, isCO2, range }) {
 
     // CO2 needs different Y-axis scale (ppm range)
     const yScale = isCO2
-        ? { suggestedMin: 400, suggestedMax: 2000 }
+        ? { suggestedMin: 200, suggestedMax: 900 }
         : { suggestedMin: 0, suggestedMax: 10, ticks: { stepSize: 1 } };
 
     const options = {