Define "Aeration"

ChiaJesus

ChiaJesus

Aquatic Metalhead
May 20, 2008
316
0
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Regina, Canada
www.riderfans.com
Heh, actually I know what aeration is, but I have a question.

I have a 55 gallon tank. Had an airpump and two airstones for bubbles. For the second time in less than a week one of the airstones broke and I vowed never to put one of those stupid things in my tank again.

So the other day I went to the LFS and picked up a Penguin 550 powerhead. It has a Venturi nozzle and were lots of bubbles. Unfortunately, this particular powerhead isn't big enough for my 55.

So today I went and bought a Fluval 4 submersible cannister filter, since I like the idea of having a second filter, PLUS it acts as a powerhead as well and has a Venturi nozzle of it's own. I am so smrt.

At first I had both units on full blast. There were bubbles EVERYWHERE! So I scaled them both back and it's better, but it's still a bubble factory.

But here's my question. In an aquarium, does "aeration" imply bubbles? Or is just water movement good enough? I.e. Can I disable the Venturi nozzle on both units (thus just having pure water flow) and still have an adeqate amount of aeration?
 
Your power heads without the air line should be enough.
 
A good HOB filter or spray bar would supply more than enough surface movement for good O2 exchange.
 
aeration is the process/a description of (depending on context) of how much gaseous exchange occurs within your aquarium (in this context).

It is affected principally by how much of the surface area of the water at the top of your aquarium (in this context) is available to exchange gas. That's why causing rippling increases gaseous exchange, because the ripples increase available surface area.

The relevant gases are mostly oxygen and carbon dioxide; like most forms of life fish convert oxygen to carbon dioxide and thus need a good source of oxygen. So when people advise increasing aeration they mean increase the amount of oxygen available to the fish.

From my own personal experience, setting up an airstone which releases tiny tiny bubbles has a postive effect of increasing available oxygen even though no ripples are formed even though it is often thought that micro bubbles of O2 are of no benefit; but I couldn't tackle any scientific objection to this belief (thankfully there are none so far:D)
 
Even more important than the slight increase in surface area caused by the minor ripples is the circulation that is bringing water from the general volume of the tank into contact with air at the surface. There need be no ripples to get good exchange but you must break up the layer of stagnant water at the surface and bring up water from deeper in the tank. If you allow stable layers of water to get established you will have well oxygenated water at the surface and a deficiency deeper in the tank. By circulating the water near the surface you break it up. I run a tank with filter only that the spray bar is several inches below the surface. Unless I let the water level get low you will never see a ripple on the surface. Oxygen content is good because the spray bar is set to discharge toward the surface so its stirring the water near the surface quite well. No stagnant layer has a chance to develop there.
 
I ended up removing the air tubing from the power heads. Thanks for sharing your experience, rbishop. Those bubbles were annoying and the powerheads were loud when the tubing was connected.
 
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