The illusion, is that more media provides better biological filtration.
The reality is , that it is not the volume of media, but the food to micro'organism ratio, and oxygen content thru the media (aeration) that determine its efficacy.
I use 3 three inch bags of rings, in my 125 gal sump as bio-media, and my testing indicates that
these 3 tiny bags detoxify all the ammonia and ntirite produced by my the fish in my 180 gal commint tank, which averages about 20, X 4 to 8¨fish.
80% of my sump is dedicated to plants, which alsp detoxify ammonia and nitrite, but also more importantly (to me) help detoxify nitrate, which most bio-media, ¨doesn´t do¨.
The recirculating flow thru my sump ia approx 1500 gph, so aeration is strong, keeping those 3 bags of bactreia totally oxygenated.
I agree with the video, stacking media on top of media does nothing positive, but that adding an airstone below media does help a lot, because it aerates the bacteria to make them more efficient at ammonia and nitrite detoxification