That thing is exactly that - a reverse waterfall. The background is 3D and has a tube "lift" cut in it with an airstone at the bottom of the "lift." There is a hole in the background at the top and the bottom to allow a mound of filter sand to be sucked into the bottom and released out the top making the waterfall. Very ingenious, but not really practical. The fine sand would be swished around the tank and the mound at the bottom would eventually not reach the hole and the waterfall would stop. It is more for show than anything. You can read an article on it with pictures in the Aquascaping magazine.
I don't think it's just lots of bubbles. It's a reverse waterfall, for sure. When a stream of water hits the surface from the below, it will create bubbles. I don't know how he did it but Dryn's explanation makes sense.
The tank is 600g and decorated with Back-to-Nature Malawi modules. A single BtN module costs at least $600! Given the tank size, he must have used several modules. The guy has some serious $$ to spend on the tank.
I think Redman is correct. It looks like a curtain of really evenly sized bubbles. At the top of where the bubbles are about the hit the surface, it looks like a stream of water is coming at just the right place to push the bubbles back down.
from Dryn's explanation, wouldn't the sand be falling down? this one, bubbles are clearly going up and I do not see sand falling down.
i did take another closer look. and it could be sand falling down, but i don't see the exit for the sand to be coming out at the to so it could fall down. and the bubbles are on the wrong side of the back ground for it to be the Reverse waterfall effect with sand.