TankMaster LED Status Meanings

Overview

The TankMaster sending unit includes a status LED visible through an opening in the lid.
This LED provides information about Bluetooth activity, connection state, and general operation.

Understanding the LED patterns can help quickly identify the current state of the device.

Where to Find the LED

• The LED is visible through a small opening on the top of the TankMaster lid
• No disassembly is required to view the LED

LED States & Meanings

Bluetooth Connected

• Color: Blue
• Pattern: Slow pulse (2 seconds ON / 2 seconds OFF)
• Meaning: TankMaster is actively connected to the mobile app via Bluetooth

BLE Advertising / Listening

• Color: Blue
• Pattern: Fast flash (0.5 seconds ON / 0.5 seconds OFF)
• Meaning: TankMaster is advertising and listening for a Bluetooth connection

Idle (No Bluetooth Activity)

• Color: Blue and Green
• Pattern: Alternating (2 seconds Blue → 2 seconds Green)
• Meaning: TankMaster is powered on but not connected to the app

Battery-Powered Units

On battery-powered TankMaster units, the LED behavior is different to conserve power.

• The LED flashes blue briefly when the unit wakes up
• Wake-up intervals are configurable in the app
• The default wake interval is every 30 seconds

If the LED is not flashing, the unit may be sleeping.

12V-Powered Units

• Idle units alternate between blue and green
• Blue fast flashing indicates Bluetooth advertising
• Solid slow-pulsing blue indicates an active app connection

What the LED Does Not Indicate

• Tank level or sensor readings
• WiFi connection status (12V units)
• Sensor calibration state

If the LED Is Off

• Verify the unit has power
• Check battery installation (battery units)
• Check wiring and voltage (12V units)

Tips for Best Results

• Watch the LED during Bluetooth pairing
• Use LED behavior to confirm the unit is awake
• For battery units, wait for the blue flash before attempting to pair

Related Articles

• Bluetooth Pairing & Re-Pairing TankMaster
• Power & Reboot Behavior
• Mounting the TankMaster Sending Unit