Why doesn’t my tank display doesn’t read empty when the tank is empty?

The resistive tank sensor should produce a resistance value of 240 ohms (American standard) or 10 ohms (European standard) when the tank is empty. One possible reason that the tank doesn’t register empty might be that the sensor doesn’t produce the correct resistance values. Another reason might be that the fluid doesn’t doesn’t go to the full extent of the sensor (e.g., the tank pickup is above the bottom of the tank). You may want to consider using the custom calibration feature of the TLA100 to configure the fluid level that you want to read ass "empty".