Sure thing!
The idea is to hold the water at a consistent level. This is achieved by measuring the current level with a ultrasonic sensor and calculating how much and how quickly the level needs to change to achieve the desired set point. Based on this calculation, a value is sent to the actuator which in turn opens or closes a ball valve. A change in the ball valve results in a change in water level which is measured by the ultrasonic sensor. This cycle repeats until the the water level reaches the desired set point.