# My DIY CO2- Barr Venturi



## Esox lucius (Feb 17, 2009)

Just thought I would share my design for DIY CO2. I had a lot of help from many members on here and would like to pass along my expereince in creating this system. I went with the Venturi- Barr style for the reactor. Sorry for the crappy pics, taken on my cell










Parts:
Rio 180 upside down with 90 degree elbow glued inside
2"x4" Viewtainer, mine wasnt this brand but same thing from homedepot
Rigid tubing
Silicone airline tubing
Aquarium sealer

Inside view- i tilted the output so if would create a slow downward spiral of flow









CO2 Yeast Generator with gas separator/bubble counter









I used 2 1.5L juice bottles with a 20 oz separator gatoraide bottle, I drilled holes smaller than tubing, cut the tubing at an angle and pulled it through. The trick with plastic is to use the right bit, I would suggest a step bit, very clean holes in plastic and you have every size hole you could want in one bit. 
http://www.homedepot.com/webapp/wcs...langId=-1&catalogId=10053&productId=100081946

I am running each generator with:
1 cup of cane sugar
1/4 tsp Champagne yeast
warm water to the shoulders

Getting about a bubble every second to every other second

I will be happy to provide details on contstruction if you need them just ask:icon_wink


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## Hoppy (Dec 24, 2005)

That looks very good. The "viewtainer" looks like it is a more sturdy plastic than the real viewtainer, so it should withstand the routine cleaning without falling apart like mine used to do.


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## core212 (Feb 23, 2009)

how does this work? does it create a vortex of sorts then spits the co2 out periodically? it looks a lot like the Red Sea Reactor 500 I have...

Here's a picture of it:


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## Gatekeeper (Feb 20, 2007)

That is not a venturi.


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## Hoppy (Dec 24, 2005)

gmccreedy said:


> That is not a venturi.


The venturi part is the upper port with the hose going back to the inlet of the powerhead. That sucks out any excessive CO2 bubble and recycles it through the powerhead, chopping it up into fine bubbles. The "viewtainer" then tends to be filled with fine bubbles in a whirlpool, with only some of them spilling out the bottom with the powerhead flow. I found this to work very well, but I didn't like having it in the tank, nor having to clean it so often. (I'm lazy)


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## Gatekeeper (Feb 20, 2007)

Hoppy said:


> The venturi part is the upper port with the hose going back to the inlet of the powerhead. That sucks out any excessive CO2 bubble and recycles it through the powerhead, chopping it up into fine bubbles. The "viewtainer" then tends to be filled with fine bubbles in a whirlpool, with only some of them spilling out the bottom with the powerhead flow. I found this to work very well, but I didn't like having it in the tank, nor having to clean it so often. (I'm lazy)


Still not a venturi, unless I am missing the Large to Small constriction of pipe flow which causes the increase in velocity due to a constriction in flow area. "Ports" don't make a venturi, the shape of the "pipe section" does.

That just looks like a suction line created by the impeller of the powerhead to me.



Anyway, so the main feed of CO2 goes into the bottom of the chamber? The flow is forced passed the CO2? It looks like a powered vortex reactor with an accessory suction line to further chop up the bubbles. Interesting.


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## plantbrain (Dec 15, 2003)

Venturi is just the suction created by flow, not the venturi **valve** which has a small constriction in the pipe that increases the suction much more, we do not need much/any constriction for the small amount of gas, for protein skimmers in marine systems, they do.
So the constriction adds much more pressure displacement between the ends.

With this, there's no constriction and the venturi pull is mild, but plenty to degas and atomize any accumulated gas.

I do not refer to it as a venturi valve. Just a venturi effect, which may not be that precise, but it's a simple concept that folks know in the hobby and understand the basic principle.

Water flowing past it, or coming into a pump creates a positive suction that pulls water and gas through it(before the pump's suction, or after it's impeller etc).

Regards, 
Tom Barr


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## Gatekeeper (Feb 20, 2007)

Venturi is not suction. I am not refering to a valve either. I am talking to the actual venturi, which is the chape of the pipe constriction.

The "Venturi effect" is the decrease in pressure of a fluid (although a gas can have fluid properties) that is accelerated through a constricted section of pipe (or a tube). Its all based on conservation of mass and the Bernoulli equation.

Just sticking a tube in a vortex that happens to have suction created by an impeller does not make a venturi.

This is suction, not a Venturi.

I would rather just agree to disagree here.


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## plantbrain (Dec 15, 2003)

gmccreedy said:


> Venturi is not suction. I am not refering to a valve either. I am talking to the actual venturi, which is the chape of the pipe constriction.
> 
> The "Venturi effect" is the decrease in pressure of a fluid (although a gas can have fluid properties) that is accelerated through a constricted section of pipe (or a tube). Its all based on conservation of mass and the Bernoulli equation.
> 
> ...


So how might you suggest a more precise way to describe the effect we are using that other aquarist might understand well?

Talk the talk is fine, but you need an alternative:thumbsup:
They call the air suction aerators "venturi"s on powerheads. 

http://www.google.com/products?clie...a=X&oi=product_result_group&resnum=1&ct=title

Knock yourself out pleading with them to change it.

I agree with you in the terms BTW. Aquarist just need the general idea/concept, and if they are really interested, they can look more in depth at the more precise definition.

Most just use it for atomization of gas(large(reef/skimmers, aquaculture, large mazzei style venturi valves) or small volumes(us-CO2)).
Whether it's technically a venturi or not..........matters little to most.
As long as they understand the concept.............that's always seemed much more important. Some words are used with several meanings and context.
It's not really going to help much at the end of the day either way. At least for our purposes here. 


Regards, 
Tom Barr


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## Gatekeeper (Feb 20, 2007)

Wasn't trying to make this a Science lesson Tom. Just pointing out that its not the correct term. Talk the talk is just that. Using incorrect terminology is never good (I don't have to tell you that.)

As far as the venturi powerhead thing... who knows. There could be something going on internally in their impeller shaft that pulls off the "venturi". Either way, that is a marketing thing to beef up the "importance" of their device over another. Just like Danner mag pump tries to pull off this "venturi" intake thing (which it technically is by definition, but certainly is not a true venturi).

I would venture to say the Mazzei is a true venturi (although I have never actually seen one in real life, just pics). The Mazzei takes advantage of the pressure drop accross the constriction of the venturi (which is going to create suction) to collapse the CO2 into the water column. Ingenious really.




> So how might you suggest a more precise way to describe the effect we are using that other aquarist might understand well?


Its just suction. Impeller is creating suction of water into the intake, just like if you draw on a straw from a glass.

BTW, I have looked at the pics in the original post above. Thats some nice clean DIY work there.


And Sorry for the thread Hijack.


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## Esox lucius (Feb 17, 2009)

gmccreedy said:


> BTW, I have looked at the pics in the original post above. Thats some nice clean DIY work there.
> 
> 
> And Sorry for the thread Hijack.



thanks, I am pretty detail oriented and I wanted to do it right, didnt think it would spark a debate, but :icon_roll, entertaining none the less. whatever you call Tom's design, it works very well.


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## Gatekeeper (Feb 20, 2007)

Esox lucius said:


> thanks, I am pretty detail oriented and I wanted to do it right, didnt think it would spark a debate, but :icon_roll, entertaining none the less. whatever you call Tom's design, it works very well.


LOL, not a debate, more of a discussion. I am not going to lie to you when I say that after this discussion with Tom, I started pulling out all my research and study books from college with a small ring of doubt of my own logic in my ears. Alas, my thoughts and explanation are still correct as described above, however, I do see where the Tom is not wrong either. Its more of a technicality. LOL.

Just to clarify what is going on here.

A venturi:









Where you have the expansion to the constriction back to expansion. 

You could make the argument that for this device you built, the impeller shaft of the power head is actually acting like the venturi constriction and the "water column" is the expanded potion on both sides. The thing that threw me off was, the impeller is actually what is "creating" the flow through the device which is in the constriction of the "venturi". Implicitly, the impeller will create suction as a result of the natural physics of the impeller creating forward movement of water.

*So, I will digress myself to say that this actually acting like a crude venturi. I am wrong in my argument above.*

BUT... I put forth this disclaimer. One thing that people should be a aware of though is that its not the "suction" that is the venturi effect. A true venturi creates suction, as a byproduct, at the constriction because of the drop in pressure as a result of the change in flow area. For this device, we are driving the flow from a static water column through the constriction and generating suction from the impeller, not creating the suction from the shape of the venturi. Its semantics, but I think we are both right somehow.

Would love to see some other thoughts on this.


I think a cooler name would have been a Powered Venturi Recylcing CO2 Vortex Reactor. LOL.


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## kid creole (Dec 25, 2008)

gmccreedy said:


> LOL, not a debate, more of a discussion. I am not going to lie to you when I say that after this discussion with Tom, I started pulling out all my research and study books from college with a small ring of doubt of my own logic in my ears. Alas, my thoughts and explanation are still correct as described above, however, I do see where the Tom is not wrong either. Its more of a technicality. LOL.
> 
> Just to clarify what is going on here.
> 
> ...


Suction, or a lower pressure region?


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## plantbrain (Dec 15, 2003)

gmccreedy said:


> LOL, not a debate, more of a discussion. I am not going to lie to you when I say that after this discussion with Tom, I started pulling out all my research and study books from college with a small ring of doubt of my own logic in my ears. Alas, my thoughts and explanation are still correct as described above, however, I do see where the Tom is not wrong either. Its more of a technicality. LOL.


And we all learned a little more about CO2, diffusing gas etc.
That's how these discussions should go forth.

I take this same approach if I am curious, go do a little home work and see.
Take a position(whether you really believe it or not, matters less) and see if you can argue the merits.

Often both ideas have merits/trade offs, neither is correct, the world is not quite black and white.



> I think a cooler name would have been a Powered Venturi Recylcing CO2 Vortex Reactor. LOL.


I think some theif took my idea some years back, so I showed folks how to to DIY for 2$ and under cut their money making scheme(50$ for their's) and they did not even get some of the core ideas from it.

As far as for the powerheads, I think needle wheel or impeller atomized aertion might be a better term. There is a difference between water pressure anytime a force acts on the water, so there's some pressure diffence.

They use this same general idea to push those water accelerators that folks put on the ends of the return out flows:

http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4585+19714&pcatid=19714

The pressure difference causes the sorrounding water to be pulled through. This requires energy and higher pressure to do and is a bit like those wave high flow Korlina pumps or the sure flo modifications to maxi jets.

It's like a very wimpy venturi. You can really drive the venturi concept harder, or go very soft.

For our purposes, particularly ith DIY, very soft is good, for larger tanks with lots of CO2, the mazzei venturi works nicely.

I like to mist the CO2, then feed it into the pump's impeller. But that's more for gas tank CO2. Here, the DIY reactor/mister worsk very effectively and is self leveling, self degassing.

Regards, 
Tom Barr


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## Esox lucius (Feb 17, 2009)

Well the setup worked a little too good, woke up this morning to 2 dead fish and the rest panting. I was getting a bubble a second. I set up the pump on the timer with the lights and added an air pump for the night time. Sucks, but I learned that lesson.


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## Spachi (Oct 27, 2008)

i tried to build something similar to this design, except with no venturi (or venturi-like) attachment. i noticed the OP didnt have an airstone, just the airtube going in to the container. why are airstones advocated by some, is there something about this design that makes them unnecessary? i worry about it getting plugged and causing a blowout someday, and if its not necessary i would like to remove it. and mine doesnt have an open bottom, i just made a dozen or so small holes for a wiffle-ball effect. it seems to work in that very few bubbles escape. oh and mine is much, much uglier.


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