Here is a tested Arduino project that uses 3 sensor probes as water level indicator with 3 leds and one LCD display + a simple controller that turns on a motor when the water has reached the desired ...

[Jens]’ device consists of an Arduino, LCD display, and two sensors – one for acetone, and another for temperature and humidity.

Whereas a typical scale would then simply show the resulting number on an LCD display, [Mirko] decided to use a moving coil meter driven by the Arduino’s analog output.