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Hoppy 09-14-2006 07:21 PM

Barr Internal Venturi CO2 Reactor
I just finished making a Barr Venturi reactor, per the sketch on Tom's website,
Barr Report - Venturi Design. I used a Catalina 400 powerhead, because it is cheap and about the right size. The tube is a Viewtainer Viewtainer Plastic Storage Container 2" x 6". The elbow at the outlet of the powerhead is from the lawn sprinkler area of the hardware store, an elbow going from 1/2" tube riser to 1/2" male threads, with most of the female part cut off so it fits into the viewtainer. I used a piece of a powerhead outlet deflector to make a prop to better stabilize the weight of the powerhead on top of the viewtainer, which has a soft plastic end cap. The suction cups are a hose retaining suction cup for a cannister filter hose, with the hose clips cut off, and everything is glued together with aquarium silicone sealant. I plan to use a small sponge on the inlet to avoid it plugging up with plant debris and snails. Total cost is around $30, including shipping for the viewtainer.

PMD 09-14-2006 07:45 PM

Barr reactor

Looks great and very professional.

What size tank will you be using it on?



plantbrain 09-14-2006 07:47 PM

1 Attachment(s)
Home Depot, OSH sell the viewtainers: 1.99$.
Rigid airline tubing: 69 Cents
Rio 180 on line: 8.99$


Martin 09-14-2006 08:54 PM

let's see it in action.

Hoppy 09-14-2006 09:47 PM

This will go into my 45 gallon tank, which has been sitting in the dining area for two months awaiting me getting all of the other stuff needed ready. The tank is a Jebo Odyssea with about 16-18 inches front to back, and about 20 inches tall.

Tom, my Home Depot doesn't have viewtainers, and if I ordered a Rio powerhead on line the shipping would have brought the price above $20. My LFS adds shipping costs to their prices, so the Rios there are more costly than the Catalina ones. I already had the CO2 tubing, and odds and ends of plastic, but had to buy 4 different elbows to get one that would work ok - those aren't that cheap at the hardware store. Plus, the aquarium sealant was $6 at the LFS. So, yes it did cost me about $30. But, I admit it could have been done cheaper.
I have been posting here about my 45 gallon tank for two months now, and it isn't set up yet, so I can't show it in action yet. That will come! I now have my continuous water change system pretty well installed, and am only waiting for a new filter sponge to be ready to start the switch over.

plantbrain 09-14-2006 11:17 PM

Yea, I know the constraints you had there for cost.
But if you had emailed me, I have all the stuff here locally and some free Anubias coffeefolia :thumbsup:

There's a version working in the tank.

Tom Barr

Hoppy 09-15-2006 12:14 AM


Originally Posted by plantbrain (Post 304423)
Yea, I know the constraints you had there for cost.
But if you had emailed me, I have all the stuff here locally and some free Anubias coffeefolia :thumbsup:

There's a version working in the tank.

Tom Barr

But, I didn't know that! In a way it's just as well. My 29 gallon tank is almost totally filled with overgrown plants now, so I wouldn't have anyplace to put any other plants - not until I get the 45 gallon tank going, and not all of the plants I have will even fit in there. I see a RAOK coming! (Especially spiral vals.)

cbennett 09-15-2006 01:06 AM

i can't seem to wrap my head around the purpose of the tubing that goes from the intake to the middle of the clear tube.

fshfanatic 09-15-2006 01:42 AM


Originally Posted by cbennett (Post 304471)
i can't seem to wrap my head around the purpose of the tubing that goes from the intake to the middle of the clear tube.

The powerhead pulls water from the tube causing a whirpool effect.

Hoppy 09-15-2006 01:49 AM

If the bubble of CO2 builds up until it reaches where the tube is it sucks CO2 back to the inlet of the powerhead to recycle it as tiny bubbles, many of which will probably escape as CO2 mist. If the bubble gets even bigger, occupying another half inch of the big tube it burps out the burp hole. This allows DIY use with shutdown of the powerhead at night, while the CO2 keeps running, but just burps to the surface. So, DIYer will have a easy way to "shut off" the CO2 at night.

BSS 09-15-2006 02:30 AM

Nice photos, Hoppy. Let us know how it works out.

Actually, it looks a lot like the first internal reactor I build for my 29g with DIY CO2. I did add an air stone to the bottom of my CO2 line to help break up the bubbles, and I certainly didn't have the feedback look and burp hole. Might have to break it out and modify it and give it a spin. Oh, and I used an old gravel vac for my 'tube' part.

Hoppy 09-15-2006 04:40 AM

The viewtainer makes it look good. And, we all know that something that looks good works good. Right? I may just use mine as an art object for awhile.

Betowess 09-15-2006 04:49 AM

Very cool Hoppy. Do you know what size tank (up to) it might be recommended for? Also, what is the GPH of a Catalina 400? I can't find it yet online. Is it around 120 GPH? Oh yeah, I just subscribed to the BarrReport. LOL

BSS 09-15-2006 11:22 AM


Originally Posted by Hoppy (Post 304532)
And, we all know that something that looks good works good. Right?

And, it does look simply mauvhelous, dahling!! (to be said in your best Zsa-zsa Gabor that should bring back some memories :)).

Thinking about my original reactor from back when, I simply attached the gravel vac opening to the output of the powerhead with the water flowing straight down. Now, I'm thinking a real key is to have the powerhead output come out at a 90 degree angle from the tube so as to get that swirling action. Hmmm. Might be worth a trip to HD to find one of those colored Viewtaners. Oh, I do so hope that they have on that matches the trim of my tank :hihi: !

plantbrain 09-15-2006 03:48 PM

They do come in a variety of colors BTW.
The 90 degree angle gets around the poorly designed commercial designed that ripped off my original idea. Some poorer designs require a sponge at the end. Those blast off and lose too much gas and are unsightly. The venturi loop always messed with others and few understood it so many never added it, another poor design mistake.

That's what happens when someone copies your stuff, but does not understands it. So I show folks the better designed and nice looking DIY model and folks can make it for 1/5th the cost:thumbsup:

Now if you keep adding more CO2, too much etc, the excess gas will burp out the hole opposite the pump and venturi side, so you have 3 ways of expelling gas from this unit/design.

1. Initially 100% dissolution
2. CO2 Mist
3. Burping slef regulation if you add too much

You never have to stop the flow gas(eg good for non solenoid user and DIY yeast folks) either. Simply turn off the powerhead to stop diffusion, the excess gas will burp out the top through the "burp" hole.

If you louse it up making it, the viewtainer is only 1.99$, so you can make another easily.

The venturi loop self regulates the CO2 level inside the reactor.
The efficacy is 100% until the gas builds up to this level, then the venturi suction from the powerhead's suction side starts pulling the gas in through the impeller and chops it up even further(2x , once in the venturi pull and then again through the impeller). The mist is gently expelled out the bottom in a downward flow and around the tank much like a diffuser disc except the mist is going down, not up and there's active flow out of the reactor.

This is also a self leveling device and bleches out any gas buld up in the reactor.

I think some copy cats thought the venturi was a bad since it appears to waste CO2, but that is not entirely true, the venturi is an advantage, not a detraction, you should have a fair amount of CO2 and be able to regulate it with a reactor, this one does that automatically for the most part if you use DIY yeast CO2.

A Rio 180 will run about a 40 gal tank, a 4x2 viewtainer is about all you need, longer and larger does not work as well as 2 such small units on either sides of the tank.

You'll also note ADA suggest multiple diffusers on larger tanks, rather than one big monster diffuser. Makes CO2 diffuser much more even this way rather than around a single point source. 4x2 reactors are easy to hide also.

Tom Barr

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