Is there an oxygen diffuser?

[Captainjr]

Can you run air through a CO2 glass diffuser to get a finer mist of air bubbles into the tank? Even my "fine" air bubble stone still puts out too many big bubbles.

 

[Fresh2o]

I've never tried that but I think you will get the same results because you are dealing with fresh water. I believe diffuser pore size, salinity/specific gravity, and water current affect bubble size. The same air stone usually produces finer bubbles in salt water compared to fresh water. I've observed that an air stone that is in the path of a strong current produces smaller bubbles. I suspect this is because the bubbles forming at the diffusers surface are forced away from the diffuser before they get a chance to "get big".
But thats my $0.02 ...give it a try if you can.

 

[aqua_chem]

Consider the following:

CO2 in the atmosphere is about .04%. This means that it's not very efficient for us to use the CO2 in the atmosphere in our tanks, necessitating the use of compressed CO2 and fairly elaborate injection schemes. Oxygen, on the other hand, is about 20% of that atmosphere (about 500x for those people keeping track), and is also significantly less soluble in water. This means that we can use the O2 in air to increase O2 levels, and the maximum feasible level of O2 is quite a bit lower. This is why we use airstones for oxygen. In essence, the disturb the surface and allow gas exchange with the atmosphere, increasing O2 and decreasing CO2 in most circumstances.

 

[Fresh2o]

Consider the following:

CO2 in the atmosphere is about .04%. This means that it's not very efficient for us to use the CO2 in the atmosphere in our tanks, necessitating the use of compressed CO2 and fairly elaborate injection schemes...

Actually this answers a question I had on why CO2 or other forms of carbon are added. I was treating CO2 like O2 but now knowing the percentages I know thats not right. So in a low tech tank with no fish where does the CO2 come from? Aerobic bacteria, plant respiration at night and atmospheric CO2?

 

[aqua_chem]

Complicated answer. Much of it probably comes from the sources you listed. Some plants are specially adapter to use bicarbonates as an alternate carbon source, such as vals. Additionally, some co2 will come In from the atmosphere, considering co2's high solubility, but it's not sufficient to meet plant's needs. In the likely event that a plant can't get enough carbon from all sources, it will stunt its own growth and in some cases cannibalize its own carbon to meet demands.


Honestly, I don't know that all the carbon sources have been adequately mapped out and proportions measured for aquatic plants.

 

[Captainjr]

So no need to use a cylinder of O2 when you can just use the air with an air pump. But I'm thinking finer air bubbles through a diffuser will dissolve better into the water with less surface disturbance. I just never saw anyone run air that way. Maybe I just need to find a better air stone.

 

[Paxdaddy]

Is there a Specific reason you are wanting to do this? Usually your filter creating surface agitation will give you plenty of oxygen In your water. Alot of people don't even use an airpump in there tanks. Are you concerned there isn't enough o2 In your tank?

 

[Captainjr]

I don't feel I have enough surface agitation with my current setup. Plus the fish seem to like swimming through the air bubbles.

 

[Fresh2o]

What kind of filter are you using and what is the size of the tank?

 

[Paxdaddy]

I don't feel I have enough surface agitation with my current setup. Plus the fish seem to like swimming through the air bubbles.

With the larger air bubbles you would be fine. The bubbles reaching the surface creates more than enough surface agitation for gas exchange