Bio-Wheel and air?

[SeaMonkeyMiner]

they say that the biowheel is better for bio filtation because it is exposed to are but im thinking the wheel is always wet so the air is never really in contact with with wheel. so wouldnt a sponge just do the same thing. am i right?

 

[TurbineSurgeon]

Nitrifying bacteria need oxygen to do their magic. Since the biowheel acts like a paddlewheel, it is constantly being exposed to air, providing an oxygen-rich environment for the bacteria. And, yes, a sponge does the same thing, although the O2 content is typically lower.

 

[michael]

> "And, yes, a sponge does the same thing, although the O2 content is typically lower."

How is the O2 content lower in a sponge?

 

[SeaMonkeyMiner]

the O2 is lower because it is submerged in water

 

[Somonas]

where did you get the 7ppm figure from?

 

[wayne]

Well you should be able to find out the maximum solubiility of any gas in water at a certain temperature. Does anybody here have a chemistry textbook with the solubilitys of oxygen and CO2 at 25C?
I'd have thought bubbling air through a sponge is just as effective as waving it in the air for a few seconds

 

[TurbineSurgeon]

You guys are losing me...

A typical sponge filter doesn't "bubble air through" it, rather it draws water through it using an uplift tube or small pump much like a UGF.

The sponge in a canister or HOB filter stays submerged, so the dissolved oxygen in the water is all the nitrifying bacteria can get. Biowheels are really nothing more than mini wet/dry filters. Although I don't know how much O2 can dissolve in H2O @ 25 C, I remember that approximately 18% of air is O2. I think I have a college chemistry text around here somewhere....

What 7ppm figure?

....and it's past my bedtime

 

[wayne]

Sorry, I should have thought how a sponge filter works. Wasn't thinking. I assume the 7 ppm crept in there as the solubility of oxygen in water (at temperature x)
I assume biowheels should work as by briefly exposing the thin layer of water to air you would be 'chaging ' it with oxygen as opposed to tasnk water which will contain much less oxygen. Numerous satisifed customers will presumably support this claim

 

[Somonas]

someone wrote that water contains 7ppm of o2, and then eddited their post.

Air contains 20.9% oxygen, 78% nitrogen and 1.1% other gasses (I am a diver, we learn this in our first open water class)

 

[TurbineSurgeon]

Somonas:

Thanks for the clarification. And I'm a divemaster, but I forgot the exact numbers