Venturi Design

Tom Barr

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Venturi1.jpg
 

AV8TOR

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Re: Venturi Design

A few questions on this design please;

What is the purpose of the cross line going from the power pump’s intake to the mid-point of the diffuser chamber? What is the flow rate of the pump? Lastly how long is the diffuser?

Thanks
 

Tom Barr

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Re: Venturi Design

This adds a fine venturi mist once the capacity limits and stauration levels(O2) have been reached in the tank. It basically pruges the gas (namely O2) when you don't need it anymore. If you keep adding more CO2 beyond this, the burp hole will burp out gas bubbles.

So this is a self leveling device but also acts to disperse (O2) CO2 well in larger tanks like a very effective diffuser stone, this is better since it also has water movement added.

Other gases besides CO2 influence diffusion. Once these levels(O2) build up about 1/2 way through the day, the reactor's abilty to 100% diffuse CO2 is greatly reduced. Then the gas bubble increases and the venturi kicks into high gear, the O2 is expelled and the CO2 is still diffused, although not 100%, this is still a very good solution to "O2 pruging" of the gas chamber.

I designed this 10 years ago and to date no one has said about why the bubble builds and why the venturi helps. Some suggested CO2 saturation levels but that is not the case. We can measure that easily.

Most folks that own CO2 reactor see a gas build up during the photoperoid, this is also directed correlated and proportional with a rise in O2 levels.

O2, unlike CO2, does not dissolve as well in water, so we have a build up in the chamber. This adds the pure O2 to the tank as well while also pruging the unit of other gases besides CO2 and allowing it to continue adding just CO2.

So there's your answer and probably more.

Regards,

Tom Barr
 

Tom Barr

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Re: Venturi Design

If the bubbles are smaller, they have more surface area to volume ratio, this should equal out = same dissolution if not more the smaller the bubble and the more contact it has with moving water.

Time is the factor I think you are likely interested in.

I think you and I need to get to the bottom your CO2 issue once and for all.

I'll go back through basic stuff, bare with me, we all need to do it once in awhile.

How big is the tank?

What are you measuring the pH/KH with?

Surface movement, filter type etc?

I have to tell folks that seem to be having the right amount to add more CO2 sometimes if the tank is not performing like it should. Just watch the fish.

How big is the reactor?

My design should be up once I get my stupid line running at home. Phone company wants 10 days. I might just go cable and say forget the phone line altogether.

The reactor I have for the site is a simple DIY internal version, this is very responsive and multiple units can be used to increase that.

I have a 350 gal tank that responds very quick now after much work.

Regards,

Tom Barr
 

chubasco

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Jan 24, 2005
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Re: Venturi Design

Tom wrote:
My design should be up once I get my stupid line running at home. Phone company wants 10 days. I might just go cable and say forget the phone line altogether.

Tom, go cable modem for broadband then get Vonage Digital for your phone.
If you make any international calls, you won't believe the savings! An added
benny is it's like an unlisted number so it's good-bye to all those people asking
for donations after you've already made your preferred donations. :) Sorry, OT.

Bill Ruyle
 

Tom Barr

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Re: Venturi Design

Got cable, works swell.

For subscribed members, I have an external DIY Reactor that removes the gas bubble to a user determined level which is also flexible and adjustable.

Only one reactor made can do this and is not set up for it and cost 150$+.
This can be made for 10-15$.

Thanks,

Tom Barr
 

Tom Barr

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Re: Venturi Design

I use a cell and will not use the regular phone at all, that will off set any additional high speed cost.
I also have wireless now.

Nothing like mobile freedom!

Now if I can transfer all that data to the laptop I'll be in good shape.
Took me 10 years, but I guess you can teach an old hound new tricks.

Regards,
Tom Barr

I'll have a diagram with labels for the DIY up soon or Greg might post it.
Subscribers will get the external version diagram and pics in a few weeks.
 

turbomkt

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Re: Venturi Design

It looks like this design is made to go in the corner (Suction cups going in two directions) with the opening pointing down. If so, is the venturi enough to disperse the amount of flow coming out of the bottom so it doesn't disturb substrate?
 

Tom Barr

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Re: Venturi Design

Yes, the flow is very gentle out the bottom end.

You could put a huge power head on a smaller tube etc....but generally this is not an issue.

This smaller unit is good for about 40-50Gal with a Rio 180.
A 6" x 2.5" tube will do a 80-90 gal, use 2 smaller ones also, they are easier to hide in larger tanks and do a better job than one single big one.

They alos use much less electric, the larger 20w vs 2 x 5w works out better there also.

Regards,
Tom Barr

Thanks Greg!!!
 

JamesC

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Re: Venturi Design

Great design. I was having problems with my old reactor, which is about 6 inches long, building up about 4 inches of O2 at the top by the end of the day. This was making the reactor pretty useless. Converted it to the new design and now works a lot better, but what a noise the venturi makes with the bubbles going through the pump. Does work very well though. I have taken the tube out of the pump for the time being and just using the blurp hole. Going to monitor but so far still seems to be working pretty well.

James
 

chubasco

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Jan 24, 2005
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Re: Venturi Design

Tom,
I was curious if you could stick a quickfilter or equivalent on the powerhead
for filtration. Or would this slow the flow enough to compromise the efficacy
of the BVD (Barr Venturi Design)? :)

Bill
 

Tom Barr

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Re: Venturi Design

Bill-

Sure, I see no reason why not.
I don't use CO2 at night personally, I really don't suggest others to do that either. Amano is in the same camp on this.

We both have our reasons.

Mine is mainly so I can dose high levekls only when it's needed. This allows me to add higher levels than anyone using a 24/7 method of dosing with much less risk and fish issues.

Since most of the 12-14 hour dark peroid has no CO2 additions, the O2 is still there(and quite high most of the time) the CO2 levels drop off and are a non issue most of the 24 hour cycle.

I can handle being hot for 6 hours a day but I'd hate being hot 24/7.

The higher CO2 also reduces O2 use by other organisms. So adding it only when you need it, allowijng the O2 to stay at a high level till it's all used up seems the best method.

Amano never said much about why, but that's the way he is.

Regards,
Tom Barr
 

chubasco

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Jan 24, 2005
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Re: Venturi Design

Thanks, Tom, having the ability to serve a dual purpose further enhances the design.

Regards,

Bill
 
F

fishface

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Re: Venturi Design

Tom Barr said:
Bill-

Sure, I see no reason why not.
I don't use CO2 at night personally, I really don't suggest others to do that either. Amano is in the same camp on this.

We both have our reasons.

Mine is mainly so I can dose high levekls only when it's needed. This allows me to add higher levels than anyone using a 24/7 method of dosing with much less risk and fish issues.

Since most of the 12-14 hour dark peroid has no CO2 additions, the O2 is still there(and quite high most of the time) the CO2 levels drop off and are a non issue most of the 24 hour cycle.

I can handle being hot for 6 hours a day but I'd hate being hot 24/7.

The higher CO2 also reduces O2 use by other organisms. So adding it only when you need it, allowijng the O2 to stay at a high level till it's all used up seems the best method.

Tom,

I have been running co2 24/7 because my ph will shoot up a fair amount if I don't. I have very soft water where I am and after a 50% waterchange I add about 8gr of baking soda to get a kh of 4(55g tank). Can I buffer my ph some more (baking soda best?) so it wont fluctuate so much? I would much rather have c02 on a timer to cut it out at lights out. I would appreciate any suggestions you might have. :eek:
 

Tom Barr

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Re: Venturi Design

pH and soft water does not matter.
Fish don't mind.

They do mind if you add lots of baking soda etc into the water suddenly.
If you have a KH of 4, there's not need to mess with 24/7, I'm trying to think of why you would need to mess with 24/7 and I cannot think of any other than you want to add CO2 into your filter, that's fine, use a solenoid for on/off in that case.

Regards,
Tom Barr
 
F

fishface

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Re: Venturi Design

perhaps i posted this in the wrong section cause it's not regarding the venturi design.

anyhow, my comment was more along the lines of how you mentioned you stop adding co2 at night which is what i want to do as well. i have a controller hooked up to my reg./solinoid which is no problem. the reason i've been running it 24/7 was to keep a stable ph. problem is when i turn off co2 at night, by morning my ph goes from 6.4 (end of day) to about 7.2 (first thing in morning). seems like a very drastic swing to me and i wanted to know how i can avoid this swing...

hope this is a little more clear and thanks for your patience :D
 

chubasco

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Jan 24, 2005
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Re: Venturi Design

If you're trying to avoid the ph swing because of your fish, that much
gradual change won't bother them in the least.

Bill Ruyle
 

Tom Barr

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Re: Venturi Design

FYI, pH dinual changes occur from 6-8 very commonly in natural lakes, 6-10 in some pools with heavy plant biomass.

This occurs daily.

There are plenty of fish.

pH does not matter.

Look at those poor unhealthy fish ADA's tanks have, every one of them turns the CO2 off at night, virtually every contest winner in the top few spoits in the ADA contest does this also.

I'd rethink your approach and rational behind stable pH with CO2 being better for fish.

Apisto's, Altums, Dsicus etc all do great, bred etc.

Guess they are not doing too bad?

Regards,
Tom Barr
Tom Barr