The video is just showing that a properly set up sump system won't overflow either the tank or the sump if there is a power outage or clogged drain. As long as the sump volume is correct there won't be enough water to overflow the aquarium if the drain is plugged and water continues to pump into the aquarium. Also, the sump should have enough capacity to hold water that drains into it in case of a power outage. A better (but more expensive setup) would have a second safety drain in case the first is plugged and a battery backup system for power outages (I've since added this in case of prolonged power outages). However, the purpose of the video was to show that a properly measured system won't overflow in either situation (a common misconception). You are correct that if you are out of town and no one is checking on the tank or feeding fish there would be problems. Not only would the pump likely be damaged running dry for days on end, but the water in the main tank would not be heated (if the heater is in the sump). When I'm out of town, a neighbor checks on the house and tank. I don't have a water top off on this tank in the video, but they are easy to set up and can take care of the problem of evaporating water. I have one on a reef tank and have had no issues. This is what I use: (www.bulkreefsupply.com/tunze-osmolator-universal-3155-auto-top-off.html)

Sorry, I had plans to run a series of videos on different aquarium topics, but never got around to it. I'm setting up a nice cichlid tank in the next week or so and am planning on doing a video of that. I may give a video update of the discus tank as the plants have changed and I've added CO2 since the initial videos were made. Thanks for the comment!

Thanks for the comment! Your aquascape looks good!