The HYDROS Skimmer Sensor is a specialized accessory designed to integrate with your existing HYDROS aquarium control system. Its primary function is to prevent protein skimmer overflows, a common and potentially messy issue in reef aquariums, by monitoring the waste level within the skimmer's collection cup. When the waste reaches a critical level, the sensor signals your HYDROS system to automatically turn off the protein skimmer, safeguarding your equipment and home from spills. Installation is straightforward, utilizing a magnetic coupling that securely attaches the sensor to any skimmer collection cup up to 1/4 inch thick without requiring modifications or new lids. This tiny sensor, with a circumference comparable to a US penny and a thickness of just over half an inch, features a purpose-built optical eye for skimmer cup environments, differing from standard water level sensors. It boasts a robust design with no moving parts, ensuring long-term reliability, and its cord is conveniently located on the magnet side for easy setup. This sensor is ideal for any reef aquarist utilizing a HYDROS control system who seeks enhanced security and peace of mind against protein skimmer malfunctions. By providing an essential layer of automation, it eliminates the worry of manual checks and potential overflows, protecting valuable aquarium equipment and preventing water damage to your living space. It's a vital addition for maintaining a stable and clean reef environment with minimal effort.