No expert here... but I cant see why an air pump will not work, as long as the sand is moving it should be fine... my understanding is when not moving the bacteria becomes stripped of oxygen causing it to die off resulting in the chaos.
Now imo you will need a decent sized air pump to get a decent movement, If it was me I would.... Install a T valve with a gate valve and then connect a cheap pump thats placed in the sump, when doing a water change you turn this pump on and open the valve, in turn the sump will still flow and sand will move without the requirement of an overflow.
Again I have never done this just thinking from what I have seen in the first video...
Now imo you will need a decent sized air pump to get a decent movement, If it was me I would.... Install a T valve with a gate valve and then connect a cheap pump thats placed in the sump, when doing a water change you turn this pump on and open the valve, in turn the sump will still flow and sand will move without the requirement of an overflow.
Again I have never done this just thinking from what I have seen in the first video...
