Aquael fanfilter plus (fan plus 1)

[excuzzzeme]

The air bubbles you see only help to assist in off-gassing the water and do not inject more air or O2 into the tank. The off gassing and added water movement is what aerates the tank.

O2 needs to be dissolved in water to be helpful and a powerhead does not have the ability to maintain the injected air into the water at a contact rate that would allow for O2 adsorption. This doesn't mean it isn't helping the water. Just not in the fashion one might expect. I too use a powerhead with air feed to help water movement.

See Star_Rider's explanation.

 

[SMinNC]

...a powerhead does not have the ability to maintain the injected air into the water at a contact rate that would allow for O2 adsorption...

With two of'em it can be done.

Well actually I had 2 PH's running two UGF plates and a 350 magnum, on a 75g. But I could sit there and watch bubbles dissapear In the water.

But ya, typically, one source of movement won't get those kinds of results.

 

[Star_Rider]

add, it's a balance.. homeostasis.

the outside air only holds so much O2 and other gases.
the same can be said of water.

there are reports of supersaturation but i wonder how long that can happen as the water will eventually reach equilibrium.
one reason when working with planted tanks and injection CO2 folks try to reduce turbulence and slow/reduce off gassing of CO2.
as we know if the CO2 injection is stopped it is a matter of time before that CO2 leaves the water column.

(IMHO)