HydroLevelControl is a bundle of hardware and software. Is designed to easily control the levels in reservoirs, pools, etc. Depending on the sensor, it can measure and control a fluid up to 21 meters, or even more (by request).
Mounting the device on a panel is easy, just make a hole with a dimension of 97 x 72mm. On the backside are the connectors for sensors, power supply, and relays. It uses 220VAC for power but can be powered over a USB port too.
The device has integrated two relays that can be configured independently from each other. Also, there is an alarming system with a sound buzzer and visual LCD background blinking, both independently configurable.
More information about the hardware can You read on the wiki page. The HydroLevelControl software can be downloaded for free here.