Air bubbler

[sawdonkey]

I use an air stone. Is it absolutely necessary?....no. I’ve run chemiclean without an air stone with no problems. The turbulence from powerheads and the return pump provide plenty or oxygen.

I use an air stone because I like the water clarity and I like that the bubbles lift the particles out of the water and into my overflow.

I don’t think you have to have experience with air stones to know they are unnecessary. Almost everyone runs a tank without them and people do fine without. I was airstone-less for 15 years.

 

[brandon429]

I'm so old school I like the way they look in action right in the display. I like the looks

Palletta's master reef build is clearly a gem. Were he to 1989 bubble wand right in the middle, everyone but me would hate that for the distraction. It's the difference to me between normal awesome or timewarp awesome. Beauty eye bhldr

 

[User]

I over-reacted, fair enough. Yes, an airstone does the same thing the skimmer does, that's the point. I only want to run the skimmer 1/2 of the day to keep more nutrients in the tank (hopefully). To compensate for the lost gas exchange, an airstone is being used.

Lol, you didn’t over-react; you were disrespectful and argumentative.

And also seem to think “fair enough” is a suitable apology.

Everything Ca1ore states is true. The bubbles themselves don’t contribute to gas exchange. The surface tension across a bubble that makes being a bubble even possible prevents proper gas exchange UNLESS that bubble can be maintained in suspension for a long time. Which aquarium bubblers are incapable of achieving. Their utility in gas transfer relies on the increased surface area caused by agitation at the surface.

You could use chemipure successfully without an air stone. All you’d need is literally a cup, a good rhythm of fill and pour to create agitation and a bunch of patience. An air stone is suggested because it’s almost guaranteed most aquarists have an air pump and stone in their box of parts.

 

[dbl]

To all... a healthy discussion and debate is encouraged here at R2R, but it needs to be done in a respectful manner, especially no name calling. A few posts have been cleaned up.

Thanks and please keep this in mind moving forward.

 

[ca1ore]

@ca1ore

Plz put Chemiclean in your tank for 2 days and dont use an airstone and let me know if your fish survive

.....bc according to you an airstone provides little to nothing as far as O2 levels in the tank.

I respectfully disagree with anyone who bases their opinions on what they've logically figured out in their head......and not bc they actually tried it and found a result.

I will continue to do what I do with my airstone.



.

Why on earth would I want to put chemiclean in my tank. If you had to do that then I agree that keeping an eye on oxygen levels is prudent. I still say that a sump bubbler is pointless, but lots of folks do lots of things that make no sense to me. Carry on ......

 

[ca1ore]

Prove it.

I have proven it on my tank by using a dissolved oxygen probe; how about you prove that a sump bubbler makes any difference. It’s laughable ....

 

[ca1ore]

The design of the "system" has nothing to do with the environment the tank is placed into.

This is a broader discussion, but the design of the system has everything to do with the environment it’s in. That you fail to understand this may explain, in part, why you feel the need to run an airstone. It’s so 1995.

 

[sghera64]

“Everything Ca1ore states is true. The bubbles themselves don’t contribute to gas exchange. The surface tension across a bubble that makes being a bubble even possible prevents proper gas exchange UNLESS that bubble can be maintained in suspension for a long time. “

I beg to differ - - and I have primary data to
prove it.

I needed to lower the pH of a 6 oz cup of water for some experiment I was doing with kalkwasser. All I needed to do is blow my breath through a sintered glass air stone for a couple of minutes. I was able to drop the pH two units and make calcium carbonate.

The cup is way more shallow than a sump or tank. It was not the surface agitation responsible for the gas exchange. It was the diffusion of gas in the relatively large bubbles into the water.

I would venture to bet that the “active” surface area of all the bubbles in a two stream flow (e.g. Paul B’s setup) exceeds the active surface area of the tank itself with just power heads.

Randy H-F has pointed out many times how difficult gas exchange is in our reefs, with regard to CO2 reduction.

In my tank I bring outside air in through my skimmer. It helped raise pH. I added an air stone via an air pump also pushing that outside air through the stone and it helped raise the pH a little more. Using power heads mixes house air (higher in CO2) with tank water and actually works against me.

 

[ca1ore]

How do you know that it was diffusion? I think it far more likely that the agitation of the sample off gassed the CO2. So your ‘data’ is likely misinterpretation.

 

[User]

You are literally arguing against physics, fluid dynamics and known gas laws.

You don’t have primary data; you have an anecdote.

Your anecdote and misunderstanding of the forces and variables at play don’t over rule hundreds of years of science fact

 

[sghera64]

How do you know that it was diffusion? I think it far more likely that the agitation of the sample off gassed the CO2. So your ‘data’ is likely misinterpretation.

Because the pH went down. My breath has far more CO2 in it that the air above the sample. That’s how I know it was diffusion from the air bubbles. My understanding of the physics is pretty solid here.

Simply bubbling room air with an air pump is what I tried first. It took too long, but gave me time to come up with the idea of using my breath instead. When i did, the pH dropped in just a couple of minutes.

The difference between these two cases is the CO2 concentration in the bubbles. The gas above the water was the same.

 

[sghera64]

You are literally arguing against physics, fluid dynamics and known gas laws.

You don’t have primary data; you have an anecdote.

Your anecdote and misunderstanding of the forces and variables at play don’t over rule hundreds of years of science fact

Were you referring to my post?

 

[User]

Were you referring to my post?

Yes

Thanks for the ‘like’

 

[sghera64]

Yes

Hmmmmm maybe I’m not understanding the claim. I know from many years of do my chemistry in the lab that bubbles do exchange gas with the surrounding liquid.

A classic exchange is bubbling HCl has into water (to form a hydrochloride salt in Pharma applications). Then there is bubbling Cl2 gas into caustic water to make bleach. One last example is sparging N2 through solvents to removed dissolved gasses in them for HPLC use. If contact via bubbles was not effective, then we would simple stir the solvent with a N2 blanket (which does work- - it just takes too long).

So what am I missing. As a Chemical Engineer, I am confused as to what physics and other established science that says my explanation of the concept of has exchange via bubble contact within a liquid is incorrect. Can you be more specific, please?

One more fact that I would like to respectfully submit is that the finer the bubbles, the faster the chemical result is obtained. Not saying the kinetics are different, it’s the surface area.

 

[User]

How many of those processes are performed either under raised pressure, increased gas partial pressure relative to average atmospheric co2 levels, or under vacuum in order to condense the volume of the bubbles to increase partial pressure.

None of these factors exist in our aquaria. Lab conditions don’t equate to hobby conditions

 

[sghera64]

How many of those processes are performed either under raised pressure, increased gas partial pressure relative to average atmospheric co2 levels, or under vacuum in order to condense the volume of the bubbles to increase partial pressure.

None of these factors exist in our aquaria. Lab conditions don’t equate to hobby conditions

All are ambient pressure + the pressure of the liquid above the dip tube. Im the lab my round bottom flask were less than 20 mm deep. The flask was at atmospheric pressure.

In addition, here is a recent reference of scientific work digging deeper into the dissolution effects taking about:

https://www.researchgate.net/public...he_gas_exchange_between_a_bubble_and_a_liquid

I understand the increases pressure effect you refer to. When I scaled up my reactions in the pilot plant (30-500 gal equipment) some times that higher pressure helped make the chemistry run faster (not always a good thing when trying to control crystal size and purity). But what usually killed me was getting small bubbles in a glass line tank with a retreat blade agitator and one lame baffle. Bubbles were too large and residence time too low. Reactions took twice as long in the pilot plant. In the lab with a metal frit, micro bubbles made the reaction go so much faster. Im both cases, the headspace is filled with the reacting has. The difference is the bubble size and bulk volume residence time. Kinda like it works on high end skimmers.

 

[User]

All are ambient pressure + the pressure of the liquid above the dip tube. Im the lab my round bottom flask were less than 20 mm deep. The flask was at atmospheric pressure.

In addition, here is a recent reference of scientific work digging deeper into the dissolution effects taking about:

https://www.researchgate.net/public...he_gas_exchange_between_a_bubble_and_a_liquid

I understand the increases pressure effect you refer to. When I scaled up my reactions in the pilot plant (30-500 gal equipment) some times that higher pressure helped make the chemistry run faster (not always a good thing when trying to control crystal size and purity). But what usually killed me was getting small bubbles in a glass line tank with a retreat blade agitator and one lame baffle. Bubbles were too large and residence time too low. Reactions took twice as long in the pilot plant. In the lab with a metal frit, micro bubbles made the reaction go so much faster. Im both cases, the headspace is filled with the reacting has. The difference is the bubble size and bulk volume residence time. Kinda like it works on high end skimmers.

Sure- but how many petco blue air bubblers do you see making ‘micro bubbles’ unless they are intentionally put through the rotors of a return pump to chop them up for bubble scrubbing?

Like I said, lab conditions using lab scale equipment =\= our hobby efforts.

 

[Ron Reefman]

To all... a healthy discussion and debate is encouraged here at R2R, but it needs to be done in a respectful manner, especially no name calling. A few posts have been cleaned up.

Thanks and please keep this in mind moving forward.

Thanks David. Hey, maybe this is a good poll question for you to start; How many reefers run an airstone? Maybe even split the yes answers in whether they run it in the sump/refugium or in the DT.

 

[User]

If you do a poll, maybe also ask why? Aeration, scrubbing, detritus mobilisation, other?

Thanks

 

[sghera64]

Thanks David. Hey, maybe this is a good poll question for you to start; How many reefers run an airstone? Maybe even split the yes answers in whether they run it in the sump/refugium or in the DT.

Hmmm interesting idea there. What would interest me most about the outcome of this poll would be if there is more than 10% of the reefers out there who use an air pump + wood frit anywhere in their system other than a skimmer. I'd be surprised if more than 10% do this.

I suspect that the evolution of the hobby, through hobbyist interest in "new and better" along with the need of designers/manufacturers to innovate and sell has caused a dramatic shift away from bubbling as a mode of CO2/O2 transport. Additionally, skimmers are very prevalent and can nearly obviate the need for these.

Another question I would pose is: what do you believe we might learn from such a poll? What would it "really" mean if less than 10% of respondents indicated they use an air stone? Does it mean it is not effective? Does it merely represent personal choice, or the power of contemporary marketing and hobby trends?