I can't speak to the cameras used in those videos, by my phone has a really hard time capturing the light imbalance. If I just take a full tank shot, with room lights on, the camera just doesn't capture what I'm seeing. The only way I can do it is by turning the room lights off, and using Orphek's 15K and 20K lenses simultaneously.
Also, I believe it's more pronounced in cases where the tank is wider than the Blade Grow itself. If you scroll back a bit to page 20 / March 7th, I posted a drawing of why I think this is the case. When the tank is more closely the size of the Blade Grow, it may be less noticeable.
I believe it's a combination of the two cases that makes it hard to see in online videos. That said, I have seen it slightly in some when the camera was focused only inside the tank. For example, look at the following video at the 27 second mark: