Today while in class, I was notified by my ReefKeeper Lite by email that one of my float switches had activated, triggering an alarm. This float switch is located in my display, and is only activated when the water level gets dangerously high.
Upon notification, I was able to completely shut down the return pump and my ATO pump. I was also lucky enough to have someone close by to check on the tank. Sure enough, the tank had filled up and my sump was full to the rim, but no water had spilled out on the floor; a disaster was averted! Floors were dry, fish were safe, and I could breathe a sigh of relief.
While I'm going to have to do some investigation and tinkering to see what I can do to prevent this issue from happening again, I was lucky that my ReefKeeper emailed me. I didn't have to leave class, and I didn't have to worry all night about what was happening. it also prevented I'd come home to in 9 hours had I not been able to catch this.
While aquarium controllers aren't necessary for every tank, I'd have to say that today my ReefKeeper earned its spot as the best (and coolest) gadget on my aquarium.