Lifting power for sponge filters: Big bubbles vs. small bubbles?

[knifegill]

My mind suggests that an open airline blowing huge bubbles is going to generate a lot more movement than an army of tiny bubbles. But the army of tiny bubbles will provide a more consistent pull instead of a pulsing one, right? Does anyone know the pros and cons of airstone vs. open line in a sponge filter?

 

[FishKeepingNoob]

I don't know the answer but looking at how the sponge filter operates, I'd say your best bet is whatever method produces the most airflow.

Seems like an airstone has the potential to throttle the volume.

 

[KaiserSousay]

If you understand how the bubble creates flow, you will answer your own question.
The bubble does not push water, but, simply put, pulls it.
Very much like a wing going through air.
The bubble moves through the water, displacing what is front.
The water flows around the bubble and rushes into the void behind it.
An unrestricted column of bubbles creates very little flow except at the very top of it`s trip through the water.
Put that same bubble in a tube and you can then generate flow.
Unrestricted, neither a single large bubble or a bunch of small, will create a flow.
So, what do you think?
Single large or bunch of smaller?

 

[ITHURTZ]

whatever has more surface area.

 

[knifegill]

It's just a matter of the actual movement created in that confined tube. The larger bubbles appear to create more of a disturbance but when I imagine the actual pulling effect as if I were the water feeling the bubbles coarse through me it seems the presence of all the tiny bubbles dispersed all through me would be more difficult to resist than one large bubble which might compress me as it passes but might not actually drag me upward that much.

 

[FishingOut]

I think the constant supply of microbubbles will be more benefitial for oxygenating the water.
Im not exactly sure, But its seems like thousands of small bubbles could push more water upwards than a couple big bubbles.
The bubbles dont "pull" water, They push it. The empty void this creates pulls water.

 

[knifegill]

'Push' and 'pull' are really subjective here. I mean, the air weighs less than the water so it rises while surface tension maintains the bubble it exists as. So this piece of air wrapped in hard surface tension goes toward the lesser pressure and on the way it is pushing some molecules with its head and dragging some in its tail. The molecules in the tail would be getting more movement out of the deal so there is more pulling than pushing going on even though both are happening. And in this scenario it still seems like many tiny bubbles will be more effective.

 

[KaiserSousay]

And in this scenario it still seems like many tiny bubbles will be more effective

Bravo!
See, you answered your own question.