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DIY Barr's venturi design reactor build

Nigel95

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Did anyone every try to make this build? It should be the 'best'

So If I understand it correctly it's a Grigg style reactor. Like this one
grigg reactor.jpg


With 3 holes drilled into it. One hole to add the co2 (as with any reactor). 2 extra holes, 1 in the top chamber and the other one 2" down from the top on the opposite side of where the co2 enters the reactor.

In the top vent you use a 3 inch rigid airline with a manual valve so it acts as a manual dump of the co2.

In one of the side holes I will connect a airline and connect it back into between my canister filter output and the reactor creating the venturi loop...? Or connect it on the inflow hoses of my eheim with something like this in between the hoses to connect the co2 tube on US $8.23 36% OFF|12/16 Mm Externe CO2 Verstuiver Diffuser Aquarium Aquarium Bubble Teller Reactor Kooldioxide Generator|CO2 Uitrusting| - AliExpress

(as I am planning to use this reactor on a canister filter) I wonder if it would also be more beneficial to use an atomizer on the outflow just before it enters the reactor. I already have this atomizers laying around. Or much better to enter the co2 in the reactor itself so it creates a bigger fighting effect between the co2 rising and the flow pushing down?

The idea about the venturi loop I think is to keep them 100% efficient and working properly. When the gas builds up it will be pulled back into your canister filter and comes later back in the reactor/ your tank.
 

Nigel95

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I am wondering what is a sweet spot in terms of length for a pvc pipe for a reactor. Ofc bigger the better for efficiency. But in terms of flow?

For my 60p with 1000lph filter I have to cut the flow on my filter. No idea what a 15" pipe will bring me. Still okay or too less flow who knows?

For my 120 I have 2000 and 1250 lph filter. Can I use a 20" on the 1250 lph and still have enough flow with both. Who knows it's hard to guess without personal experience and every setup is different.

Also a PITA to keep rebuilding it..

Any input? Im leaning towards the Griggs style with Barr mod on it to have less flow reduction than a Cerges style.
 

Nigel95

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I think you should consider a by pass and adjustable flow as there are no set figures to go by.
However a simply analogy would be ... the longer the bubbles are in suspension the more likely there are to dissolve.
How is this design in your opinion? Some guy in my country makes one. Not cheap as DIY but if it works.. Price is €100 My idea was to let him drill another hole same height as where the co2 enters. And make the Barr venturi loop to get rid off the co2+o2 build up. Plan is to put the airline from the reactor back in the filter hoses. Preferable inflow but if that's gonna give build up in the filter guide it between the filter output and the reactor?

Screenshot_20201207_175118.jpg



What do you think @Zeus.
 

Zeus.

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What do you think @Zeus.

1. The reactor is on the small size 150mm diameter would be my choice, plus reactor too short for its diameter, Wide and short works or long and slimmer, as its the flow rate in the Reactor that forces the bubbles down
2. CO2 input should be much closer to bottom, just above the outlet.
2. CO2 feedback to venturi should be the top of reactor
3. Feedback needs to go to an area of lower pressure than the CO2 reactor chamber for it to work, so needs to be a constriction to flow pre CO2 reactor, so fitting it
Plan is to put the airline from the reactor back in the filter hoses.

would fail without a pressure drop so need venturi constriction which the unit doesnt have ATM

1607361738362.png

4.Think its meant to be a bubble counter, which IMO is a waste, as doing point 2 would make the Reactor chamber a bubble counter
5. A union joint and gate valve on reactor exhaust may be very handy when needed for service.
6. Reactor has no swirling of flow in CO2 chamber which 'Foxy' had in his.

I think it would fail as the CO2 reactor would fill up with CO2 as no atomiser/ diffusor is present. I would give it a miss.
 

Nigel95

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Appreciate the input man! @Zeus. Yeah the bubble counter I was not planning to use its an option you can choose for and couldn't find a pic without it. I have a bubble counter in the co2 art regulator anyways.

I think I'm go stick with my atomizer haha. Those reactors are a rabbit hole. Guess there is still no successful commercial option around? I'm not that good in DIY so I think I'll pass!

Did anyone ever use something like this. Looks too compact for what it claims it does?

Amazon product
 

Hanuman

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Any input? Im leaning towards the Griggs style with Barr mod on it to have less flow reduction than a Cerges style.
Yes I would suggest that. Cerges style reactors would be more suitable for bigger tanks. Flow is also reduced compared to Grigg style reactors. Tom's reactor is the simplest and perhaps the most efficient I have seen so far compared to all those mods out there.
 

Hanuman

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1. The reactor is on the small size 150mm diameter would be my choice, plus reactor too short for its diameter, Wide and short works or long and slimmer, as its the flow rate in the Reactor that forces the bubbles down
2. CO2 input should be much closer to bottom, just above the outlet.
In general Rex Griggs style reactors tend to be ~50mm in diameter and ~300mm long. Those are the base dimensions which obviously can be adapted according to the tank size/need. It's a matter of tweaking things because it also depends on the filter's power/flow. This 150mm for a Rex Griggs reactor is way too much. Perhaps you are referring to a Cerges type reactor. Also, the reactor in that picture has a bypass with flow valves. So technically you can regulate flow in that chamber but I don't think you need a bypass for smaller tanks. But my opinion though is that the reactor in that picture is way too bulky
6. Reactor has no swirling of flow in CO2 chamber which 'Foxy' had in his.
Rex Griggs style reactors are made so that swirl is not needed. The height of the reactor takes care of co2/water contact time. Only Cerges style reactors which are shorter would benefit from swirling to increase Co2 contact time.

I think I'm go stick with my atomizer haha. Those reactors are a rabbit hole. Guess there is still no successful commercial option around? I'm not that good in DIY so I think I'll pass!
Ultimately they all have the same purpose. Increase Co2 contact time with water. That's all. There is no magic to it. The good thing about the Rex Griggs version is that it takes less space. The Cerges version can be more bulky. Also the venturi port is highly recommended to allow back pressure to be released usually later in the day when the reactor has started accumulating Co2. The reason there isn't many commercial products is mostly because these reactors are dependent on tank size and water flow so it's difficult to have a one size fits all. There are a few though. Nilocg does produce some of these reactors (Cerges and Griggs). There are a few others as well.

Here are two that I built. 2inch diameter ~14inch long. Don't pay attention to the big top ports. The picture was taken when I was dry fitting all the parts.

IMG_4429.jpg
 
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Zeus.

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In general Rex Griggs style reactors tend to be ~50mm in diameter and ~300mm long. Those are the base dimensions which obviously can be adapted according to the tank size/need. It's a matter of tweaking things because it also depends on the filter's power/flow. This 150mm for a Rex Griggs reactor is way too much.
But are these the best dimensions or just what happens to be the dimensions that can easy fit under most folks tanks ?

IMO/IME a wider reactor will have a lower flow rate so the bubbles will have more chance to dissolve without being forced out of the bottom of the reactor, so wider the better, plus a wider reactor will have a larger surface area of the big bubble at top- but it needs to fit under the tank and in the base ideally.

Having run my CO2 reactors with high and low flow I have found
1. The time it takes to get the pH drop is unchanged with high or low flow Nano or big bubbles
2. High flow though reactor is noisy and low flow is silent with door close even with my injection rate
3. Nano bubbles get back to tank more with high flow less with low flow.
4. Big bubbles tank remains clear (except pearling)
5. Having media in do not change the pH drop time - no media means nothing to clean
6. I have not touch my reactors/atomisers for well over a year, the few times I did clean them in the past I found very little in them detritus wise

With my twin CO2 reactors and twin injection/solenoids which I control with an industrial timer 'PLC' I can get well over a 1.0 pH drop in 500l tank in less than 30mins. which is unheard off anywhere else as far as I am aware. I have twin JBL ProFlora Direct Inline CO2 Diffuser which to be honest the CO2 bypasses the ceramic element, I could seal them however I get big bubbles, I get the pH drop and tank is clear as a bell - so job done.

APS EF2 are cheap, they dont have the best sealing system and with plumbing (below) I did blow one of the lids off once filling the tank when I turn the water on too fast, it was easy to fix just needed lid popping back on. Now when filling tank I close the valves on them, other wise no issues
1607422044468.png

I plan to drill holes in lids of reactors so I can feed the CO2 back into the system via venturi, I plan to add a constriction as shown on pic above as have a ventri system that I can just the hole size like in a carburettor for fine tuning, do away the the atomisers and have CO2 injected slightly above CO2 reactor outlet( maybe with a fitting so could add bazooka)

My thoughts/plans ATM
 

Zeus.

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Nigel95

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Looks nice! Did you also add a venturi loop in the end or did you skip it? If so did you put the venturi loop back in the outflow or inflow hoses? Or a dedicated pump?

@Nigel95
APS EF2 £20
16mm Y PVC HOSE CONNECTOR x2 £8
Plastic Irrigation In Line Barb Valve 16mm £5
Inline diffusor of you choice, some hose, clips
It will work and value will give control of bubbles in tank. But will it fit in the space 😬 as running hoses smoothly needs space
Seems like a really easy option for not much DIY and cheap... About the space well... My 60p is on an simple table and the filter next to it. Could get messy with this setup...

For my 120 well yeah there is just a 120x60x80cm cabinet under the tank. Need to fit 2 filters + 6kg co2 bottle there. And this setup. I do have co2 art elite regulator so was planning to use 2 atomizers on both filter one. What would you recommend for a 360l tank. one or two aps ef2 canister filters?

Do you have any idea how much space approximately it takes to fit one of those setups you mentioned?

Would love to add that venturi loop as well as it seems a nice way to get the o2 + co2 build up back in the system. Are you going to push it back into the filter so the impeller chops the gass up. Or more safely but less optimal.. back into the outflow hose before the APS EF2 . I'm not sure if it's a problem to push the gass back in filter disturbing things?

Regarding the APS EF2 method the goal is no mist right? It's not truely efficient as the other reactors is that right? Co2 is cheap as you said :)
 

Hanuman

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But are these the best dimensions or just what happens to be the dimensions that can easy fit under most folks tanks ?
These are dimensions that have been tested and proven to work. There is no need to oversize things when it's not needed. Now you can certainly vary dimensions but these are what works for most folks. At least that's what I have read over and over again. Obviously the bigger the tank and the bigger the reactor needs to be since you'll have bigger pumps with stronger flow. The whole idea is to slow the flow and break bubbles small enough so that mixing with water is optimal. How you do it doesn't really matter. These 2 designs Rex Griggs and Cerges do exactly the same, just with different hardware.
I plan to drill holes in lids of reactors so I can feed the CO2 back into the system via venturi, I plan to add a constriction as shown on pic above as have a ventri system that I can just the hole size like in a carburettor for fine tuning, do away the the atomisers and have CO2 injected slightly above CO2 reactor outlet( maybe with a fitting so could add bazooka)
Yeap that's good. The further back you put the Co2 the better. Here Tom's Barr way:
Dual venturi DIY External CO2 reactor
And here is the method I used:
Aquatic Plant Central - View Single Post - DIY Inline reactor plans
(the post is not from me but I did the same)
 

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