# Air in aquariums



## Unrulyevil (Jan 10, 2007)

Hello. I have rather silly question. *Why does one need air pump and air supply in to the aquarium rather than fish need it.


THX*


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## beetlebz (Aug 2, 2007)

It is my understanding that the air only serves to disrupt the surface of the water, where the bubbles break at the top of the aquarium. this disruption increases the surface area of the water which allows more oxygen transfer into the water 

im sure im atleast a little off base but thats the rough idea  Im sure Ron, Lupin, F4A or the like can offer a far more intelligent explanation!


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## coley (Jun 23, 2007)

That's how I understand it also. I have air pumps in both my tanks because I like the way it looks and my fish like to play in the bubbles.


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## herefishy (Dec 14, 2006)

The reason that air is run into the tanks is four-fold. (1.) To provide surface agitation and enhace the CO2-O2 Transfer. (2.) Many filtration system use air to provide water flow to make the system work. Examples are ugf's (undergravel filters), sponge filters, box filters, and others. (3.) To provide current in the tank. (4.) Some use the bubbles for ornamentation, it just plain looks nice.


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## mHeinitz57 (Jun 9, 2007)

an air bubble has a surface area itself and therefore saturates oxygen into the water as it rises. It will cause some surface agitation but it does so much more than that. In any fish tank there will be a greater ammount of oxygen at the top of the tank and the disolved oxygen (DO) decreases the deeper into the tank you go. This is why shallow tanks do not need aeration as much. A deeper tank should have aeration do that oxygen will dissolve in the deeper portions of the tank more. ALso note that an airstone is meant to break up air instead of releasing large bubbles. This is to allow a greater surface area of bubbles and more oxygen absorbtion into the tank. So it does a lot more than just disturb the surface and make the tank look fun.


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## Unrulyevil (Jan 10, 2007)

and I will answer portion of my question myself 

most importantly you need air in your aquarium to support your natural cycle meaning bacteria that thrives in your gravel and feeds on ammonia in your tank.


thanks people!


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## caferacermike (Oct 3, 2006)

I absolutely hate bubbles in my tanks. The only bubbles I see rising from the floor of a lake are hazardous methane bubbles. I prefer using sumps to agitate the water creating the exchange and huge, I mean huge, power heads to disrupt the flow of water all over the tank.


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## herefishy (Dec 14, 2006)

Using powerheads with massive gph is ok in some circumstances. I can just see my dwarf cichlids with teir faces smashed against the glass because of heavy currents. lol


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## jones57742 (Oct 31, 2006)

mHeinitz57:

Do you have a reference which you could direct me with respect to your post?

TR


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## mHeinitz57 (Jun 9, 2007)

jones57742 said:


> mHeinitz57:
> 
> Do you have a reference which you could direct me with respect to your post?
> 
> TR


Nope, being a college student you learn not to reference just anything you find online but only scholarly articles/citations. With respect to aquariums unfortunately there aren't a lot of scholarly publications. That being said I still do research online and in magazines but much of my information just comes from basic understanding of physics, chemistry and fish care. With respect to my statement that oxygen from bubbles will directly dissolve into water I'll direct you to a similar invention in the fish industry...the CO2 injection system. These systems use a slower rate of bubble and often use a track that the bubble travels along for awhile before being released to the surface. The purpose of this is not to aggitate the surface but to allow CO2 to dissolve into the water from the bubble directly. You have to understand that the surface of your tank is just a big surface of a bubble (that bubble being the outside world). If you agree that oxygen gets dissolved there then you must agree oxygen gets dissolved from a bubble at greater depths. I personally use live plants alone as my oxygen source and i'm pretty sure they don't agitate the surface (unless they are partyin while i'm in bed, lol).


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## jones57742 (Oct 31, 2006)

Mh:

Please let's keep going on this as many folks may be interested in our conclusions (especially Ron).

I am not only not familiar with CO2 injectors but have never even seen one so please "bear that in mind" with respect to my verbiage set forth below.

Air bubbles would not exist without surface tension.
Do you agree or disagree?

I have never therefore believed that the transfer of atmospheric gasses through the surface of the bubble was very, very minimal.

If the air bubbles could "somehow be broken up" in such a manner as to not form smaller bubbles then increase oxygen saturation might be possible.

If you agree that oxygen gets dissolved there then you must agree oxygen gets dissolved from a bubble at greater depths.
I do not.
Smaller bubbles have greater surface tension per unit of surface area with respect to volume than larger bubbles.
A bubble will expand as it moves toward the surface due to the pressure (potential energy) at the lower depth.

the surface of your tank is just a big surface of a bubble (that bubble being the outside world).
I do not think so.
An air bubble exists in the water medium due to surface tension.
Yes surface tension exists on the surface of the water in the tank but is about epsilon^2.
Hence the significant exchange of atmospheric gases to the tank water at the surface and not via the air bubbles.

(unless they are partyin while i'm in bed, lol).
This is a good one!
I am not being an adversary here!!!
I would enjoy working through this one as I have never "run into" this issue being discussed in the literature and you are probably "way ahead of me in" chemistry and fish care.

TR


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## thorpe84 (Sep 1, 2007)

dont you love it how you get like 10 answers from different people saying the same thing just said in a slightly different way?


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## mHeinitz57 (Jun 9, 2007)

lol, yes I agree thorpe. I am in no way saying that aeration beneath the surface is the main source of dissolved oxygen and I am especially not saying that oxygen does not dissolve at the surface. Surface tension refers to the strength of molecular bonds of water molecules and is not an impermeable force. All I am stating is that oxygen will be absorbed from an air source below the surface. I am in agreement that most of the absorbtion is from the surface of the tank though.


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## jones57742 (Oct 31, 2006)

mHeinitz57 said:


> . I am in agreement that most of the absorbtion is from the surface of the tank though.


Mh:

Thanks for posting.

I feel better now knowing that I have not been promulgating "bad assertions" to folks.

TR


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## mHeinitz57 (Jun 9, 2007)

hey "no" problem sir. I don't even use "air" pumps and my "tank" is 3 ft deep with not a lot of "surface area". My several plants and good "filtration" work wonders, lol.


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