[MiamiAG]

We've all seen them- a cylinder with a powerhead hooked up to it that generates turbulance and "theoretically" increases the diffusion of CO2 into aquarium water. On the flip side is the good, old bell diffuser- a simple bell-shaped object into which CO2 is bubbled into.

Is one truly better than the other?

Does turbulance really increase diffusion?

 

[MiamiAG]

Tony,

A bell difusser sitting in the aquarium would have aquarium water passing by it constantly. I guess you can view it as one large bubble.

I understand that you are saying that the more surface area created with CO2 (which many tiny CO2 bubbles would have more than one single large CO2 bubble) would allow more CO2 to diffuse into the water column or at least at a faster rate.

Certainly nitrogen and oxygen would diffuse out of the water and into the large bubble in the bell diffuser thereby decreasing the CO2 content. Perhaps this also creates inefficiency.

However, why would a power reactor be any more efficient then a scintered glass diffuser sitting at the bottom of the aquarium creating tiny bubbles then?

Also, as for no bubbles escaping from reactors, how can that be if nitrogen and oxygen (barring other gases) would replace the CO2 in the bubbles? Wouldn't there have to be bubbles remaining but just bubbles filled with nitrogen and oxygen?

 

[MiamiAG]

Steve,

Why would there be lower pressure in a filter? I would imagine that a pretty good differential in pressure would be necessary to result in any measurable difference in CO2 diffusion.

Also, would decreased pressure increase CO2 diffusion or would an increase be needed?

 

[MiamiAG]

Steve,

Thanks. I still don't understand the pressure in filter thing. Perhaps Tom will chime in. I can certainly understand bubbling CO2 into the intake where the bubble will get held up inside the filter thereby providing time for CO2 to diffuse into the water.

As for the difference between reactors and diffusers, the only difference I can see is contact time. I am assuming that a tiny bubble created by a diffuser will not have enough time to diffuse all of the CO2 out if it by the time it reaches the surface and degasses into the atmosphere.

I am also assuming that the CO2 bubble in a reactor is trapped until all CO2 diffused. However, if no bubbles exit the reactor, I don't know where the N and O bubbles would go?

 

[MiamiAG]

Diffusers create tiny bubbles that, as Steve mentioned, have MUCH more surface area than bubbles typically created by reactors. These 100% CO2 bubbles will immediately begin diffusing CO2 because of the lower CO2 content in the water column. Likewise, N and O2 will diffuse into the bubbles because of their lack in the bubble. When the bubble reaches the water surface, it will be mostly, if not completely, N, O2 and other gases. The CO2 will have diffused into the water.

In my experience, I have not found power reactors to be more efficient than a good diffuser. Yes, they trap the bubbles until all CO2 is diffused, but is that really necessary? Are we so sure that a tiny CO2 bubble created by the diffuser doesn't release 100% of its CO2 also? Perhaps even quicker?

Power Reactors are bulky, unsightly and require a powerhead to work. The addition of another electrical gadget to me is not worth it.

Diffusers can be well hidden in the aquarium and are easy to clean. I simply dip it for a few minutes in a water/bleach solution for a few minutes every month. Not much to it.

 

[MiamiAG]

Tony,

Bell diffuser yes, but a small diffuser like the one I have on auction is virtually invisible.