I use a Hydrolab sonde to monitor lakes in Washington. It worked great until the day I lost my mind, forgot to plug in the cable, and lowered the probe over the boat. Whoosh! The unconnected sonde dropped like a torpedo. Instinctively, and stupidly, I dove into the dark murky water to grab it. Too late. It plummeted 28 feet to the bottom, which is a muddy soup with no oxygen and high levels of corrosive hydrogen sulfide and ammonia. I assumed the sonde would be impossible to find and likely ruined. A month later, nearby divers agreed to take on a lost cause. They groped for hours in complete darkness shoulder-deep in mud. Just as I was giving up hope…one of the divers burst to the surface, waving the sonde triumphantly. In spite of “deploying” my sonde in such harsh conditions, after cleaning and recalibration, it worked flawlessly with all data intact despite the exposed pins. I still get high quality data from my 12-year old Hydrolab. It is a rugged and reliable piece of equipment.