Willie Engelbrecht describes using Grafana Cloud and an ESP32 microcontroller to monitor a home water softener's salt levels to prevent the issues caused by hard water, such as dry skin and pipe damage. After moving to an area with hard water, Engelbrecht decided to create a cost-effective solution instead of purchasing expensive water softeners with built-in sensors. By utilizing Grafana Cloud's capabilities, Engelbrecht set up a system to track salt levels in the water softener using a JSN-SR04T distance sensor and ESP32 microcontroller, which sends data every two hours to Grafana Cloud for visualization. This setup allows Engelbrecht to receive alerts when the salt levels fall below a certain threshold, ensuring timely replacement and preventing the return of hard water. Engelbrecht highlights the integration with Grafana Cloud as an easy way to manage metrics and expresses satisfaction with the project, hinting at future IoT projects.