If an alarm sounds in a hatchery and no one is around to hear it does it still make a noise?
The alarm is a good idea actually, my tank is downstairs and with my shift work I don't always get a chance to check it regularly. My wife works from home though, so would be able to hear the alarm from her office. Digital monitoring is the way to go, IMO there's plenty of money to be made for the first person to come up with some sort of basic monitoring equipment linked to a smartphone app that doesn't cost the earth.