Haha …
the world is so small.
This is my cistern…
The TF-FT002 has been in e-waste for a long time.
The ultrasonic-sensor is probably defective.
I bought an extra ultrasonic-sensor from the UK and installed it - unfortunately no success.
The part is not suitable for very wet rooms.
Too bad now there is an app for it 
Sorry, I think these parts don’t live longer than 2-4 years
I’ll look around for an Oilfox.
good luck 
