A few minor quibbles, but the general idea is not bad.
Current in the tank does not in any way guarantee freedom from protein/bacterial films on the water surface. I have very high current tanks which develop films. To avoid the film with water movement, you must break the surface.
The author is confused in saying:
"The fifth reason why we should pay attention to water movement is because moving water carries oxygen to the denitrifying bacteria in your tank?s substrate. It?s these bacteria that are responsible for the breakdown of harmful waste products (i.e., ammonia and nitrite). Their breaking down ammonia puts it into a form that allows your plants to use it (i.e., nitrate)."
Denitrifying bacteria do not change ammonia and nitrite to nitrate. Denirtifying bactera reduce nitrate to nitrite, ammonia, and nitrogen gas. Nitrifying bacteria oxidize ammonia and nitrite to nitrate. These nitrification bacteria may be at and very near the surface of the substrate, but their oxygen demands are too great to exist more than millimeters below the surface in other than UG/RFUG situations. Denitrifying bacteria are deep in the substrate, where other than in UG/RFUG situations, the oxygen tension is very, very low - these are anaerobic bacteria, oxygen is toxic to them.
Plants do not normally flourish in tanks with strong surface distruption, as it does blow off dissolved CO2. Submerse plants generally require dissolved CO2 as their carbon source - and carbon is more than 40% of their dry weight.
The fourth reason is equally debatable. I am very conservative and old-fashioned on many aspects of tank-keeping. I do not believe in "artifically increasing" the carrying capacity of the tank by obligate aeration. I live in an area subject to frequent, usually but not always brief, power outages. If you have artifically increased the carrying capacity of your tank with aeration and you are away from the house when the power goes out, you just well may return to dead fish. Even if not that extreme, you will return home to crisis. No thank you, not in my fish tanks.
But the basic point is that in most tanks (not discus or a number of other fish), current is likely to be less than optimum. This is in part why I multifilter all my tanks, and why I frequently customize my canister return spraybars - you can set tanks with no dead zones. Even in planted tanks current is important - it helps disrupt the boundry layer effect and delivers nutrients to the plants.
