# Anybody use this Chinese External CO2 reactor?



## Magoo (25 Jan 2021)

I'm currently using the Qanvee inline CO2 diffuser. It works well enough but the bubbles it generates is becoming tiresome to look at. I'm planning to shift to an external reactor but I just don't have the inclination or time to source the parts for a DIY project. Has anybody try this reactor? What are your thoughts?




			https://shopee.ph/CO2-Aquarium-External-2601HL-Atomizer-Fish-Tank-Water-Plant-Diffuser-HOT-SALE-i.328408899.3175047791


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## Zeus. (25 Jan 2021)

Well going of the pics my initial thoughts are 🥳🥳🥳🥳, even check to see if I could get one/two off ebay, that could be converted into a venturi feed CO2 reactor very easy IMO
Having a needle value on the CO2 feed is great also.


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## zozo (25 Jan 2021)

It looks almost identical to my DIY fluidized sand bed filter I made a few years back.
If it doesn't work out as CO² reactor you could reconnect it in reverse and use it as a fluidized sand bed filter.


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## Magoo (26 Jan 2021)

Thanks for the input guys. I'll purchase one and try it out.


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## Nigel95 (26 Jan 2021)

Magoo said:


> Thanks for the input guys. I'll purchase one and try it out.


Let us know 


Found it on Ali as well
https://a.aliexpress.com/_BT4BJr


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## Regent (6 Feb 2021)

That looks interesting. @Zeus. What modifications would you make?


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## Libba (6 Feb 2021)

How does it work?


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## Zeus. (6 Feb 2021)

Regent said:


> What modifications would you make?



Well going off the pic only.
I would just make a ventri adaptor to fit on the 
Just checked out the conversion rate



Well worth a try IMO, I would like to get my hands on one and try it out.

I would make a DIY Ventri  like @Hanuman did for his CO2 reactor from basic tube connectors (pics of Hanumans below)










Fit this pre CO2 reactor as far away from the CO2 reactor as possible.
Heres Hanumans reactor




Although most folk use an inlet for the CO2 (blue cross on pic) I don't think it is necessary 'if' using a ventri to recirculate the CO2 in the influx of water via the venturi esp if not using an atomiser in the reactor. So I would 'Tee' into the return feed to the venturi and have a check valve between the 'Tee' and the CO2 regulator.

The needle valve on top of the 'new CO2 reactor in link' I would use to control the return flow to the venturi.

That is what I would do, I fully believe it would work but have not tried it.

If anyone finds we can get it imported please post ands I will get one also


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## Hanuman (6 Feb 2021)

So far mine is working great. Venturi is working like a charm and CO2 is being recirculated back into reactor when the CO2 in the chamber reaches the preset level. There are two small mods I would do to mine though:
1 - to make it slightly taller. I do see some bubbles being sucked out to the outtake. Not many though.
2 - use rigid tubing for the purge ports that go down into the reactor but impossible to find that type of tubing where I live.

Here are a few high res pictures for the posterity.


 

 




 

 

 



And the video:


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## CJayT (7 Feb 2021)

I wonder... Why not put an inline diffuser  into the water in line, wouldn't the smaller bubble diffuse faster??


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## Zeus. (7 Feb 2021)

CJayT said:


> I wonder... Why not put an inline diffuser  into the water in line, wouldn't the smaller bubble diffuse faster??



Yes, and smaller bubbles get pushed further down in flow of water in reactor and can end up in return to tank so need taller reactor 😬😬😬, so bigger bubbles in reactor give a bubble free tank


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## Maf 2500 (12 Feb 2021)

Zeus. said:


> Yes, and smaller bubbles get pushed further down in flow of water in reactor and can end up in return to tank so need taller reactor 😬😬😬, so bigger bubbles in reactor give a bubble free tank


That is interesting to know, thanks. (I am planning an internal reactor connected to a powerhead/circulator and was not sure if connecting the CO2 tubing to the venturi air in nozzle would work best, or if I would need some kind of diffuser. Different to the reactor being discussed here but the principle would be exactly the same.)


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## Nigel95 (12 Feb 2021)

Magoo said:


> Thanks for the input guys. I'll purchase one and try it out.


Did you use it? What is your experience so far?


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## Magoo (13 Feb 2021)

Nigel95 said:


> Did you use it? What is your experience so far?


I haven't gotten around to getting one yet. I'm ordering one tomorrow.


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## ForestDave (14 Feb 2021)

Just found this tube connector. Would this work as a venturi or do you need the 1/4 CO2 pipe to stick out inside the larger pipe with the bevel facing away from the flow? 








						Claber Main Tube Coupling Reducing T-Joint 2 Pack
					

Order online at Screwfix.com. Used to branch off ¼



					www.screwfix.com


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## ForestDave (14 Feb 2021)

What glue did you use for making the diy venturi please @Hanuman?


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## Zeus. (14 Feb 2021)

ForestDave said:


> Just found this tube connector. Would this work as a venturi or do you need the 1/4 CO2 pipe to stick out inside the larger pipe with the bevel facing away from the flow?
> 
> 
> 
> ...



does it have a constriction?



Without a constriction its a no go, although you could fit it with an insert to make a constriction, glue it in place and then drill thought it 

Although with second thoughts the fitting is the constriction so *Yes* it should work, great find , what sizes do they do?


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## ForestDave (14 Feb 2021)

Zeus. said:


> does it have a constriction?
> View attachment 162797
> Without a constriction its a no go, although you could fit it with an insert to make a constriction, glue it in place and then drill thought it
> 
> Although with second thoughts the fitting is the constriction so *Yes* it should work, great find , what sizes do they do?


Cheers. 
I think it’s just 1/2” with a 1/4 inlet.


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## Hanuman (14 Feb 2021)

ForestDave said:


> What glue did you use for making the diy venturi please @Hanuman?



Epoxy glue. You need to find one that doesn’t harden too hard but keeps some sort of elasticity. Also it’s best if you sand the parts that will glue for better adherance.


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## ForestDave (14 Feb 2021)

Thanks. 👍


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## ForestDave (16 Feb 2021)

Two thoughts. 
I'm keen to make one of these but as the clear pipe in the UK is not massively cheap, can you see any major issues with making it out of cheap bog-standard white or black pipe and just keeping an eye on the drop checker and bubbles or lack of bubbles entering the aquarium. (I understand it's much easier and more fun with the clear pipe). 

Lastly, are the shop-bought CO2 reactors from say CO2 supermarket not worth buying, or do you guys just love making things and striving for perfection? (Not a bad reason, I love a DIY project myself but just wondered!)


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## Zeus. (16 Feb 2021)

ForestDave said:


> are the shop-bought CO2 reactors not worth buying,


IMO nope, if there was one that was I would get it.


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## Hanuman (16 Feb 2021)

ForestDave said:


> I'm keen to make one of these but as the clear pipe in the UK is not massively cheap, can you see any major issues with making it out of cheap bog-standard white or black pipe and just keeping an eye on the drop checker and bubbles or lack of bubbles entering the aquarium. (I understand it's much easier and more fun with the clear pipe).


It's just a piece of pipe so technically anything will work, transparent, blue, white or black. The clear PVC has one major advantage. You can see what is happening and so give you some feedback on whether it's working right. That's why most people use the transparent PVC. But yes it's much more expensive than the standard colored PVC.



ForestDave said:


> Lastly, are the shop-bought CO2 reactors from say CO2 supermarket not worth buying, or do you guys just love making things and striving for perfection? (Not a bad reason, I love a DIY project myself but just wondered!)


Yes and no. The reason rests on the fact that you can't use a one size fits all reactor. The bigger the tank, the bigger the reactors needs to be (either higher or wider). The proper functioning of a reactor depends on its capacity to slow water flow enough so that CO2 does not escape through the outflow.
If you go for a Rex Grigg I would suggest a 2inch diameter and ~24inch tall (at least 20inch). I made a 15inch tall reactor and retrospectively I realize I should have made it taller. I have a 160L tank.


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## ForestDave (16 Feb 2021)

Hanuman said:


> It's just a piece of pipe so technically anything will work, transparent, blue, white or black. The clear PVC has one major advantage. You can see what is happening and so give you some feedback on whether it's working right. That's why most people use the transparent PVC. But yes it's much more expensive than the standard colored PVC.
> 
> 
> Yes and no. The reason rests on the fact that you can't use a one size fits all reactor. The bigger the tank, the bigger the reactors needs to be (either higher or wider). The proper functioning of a reactor depends on its capacity to slow water flow enough so that CO2 does not escape through the outflow.
> If you go for a Rex Grigg I would suggest a 2inch diameter and ~24inch tall (at least 20inch). I made a 15inch tall reactor and retrospectively I realize I should have made it taller. I have a 160L tank.


Thanks Hanuman. 
I'll probably wait a bit and get a clear pipe in that case. Cheers for the tip on the height, my tank is probably about 160L once filled with AS and rock. 
Out of interest, do you think narrow and tall is better than wider and shorter as it may condense the bubbles into a tighter space?


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## Zeus. (16 Feb 2021)

Hanuman said:


> The proper functioning of a reactor depends on its capacity to slow water flow enough so that CO2 does not escape through the outflow



Plus the slower the water in the chamber the higher the pressure the better a Venturi works


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## Hanuman (16 Feb 2021)

ForestDave said:


> Out of interest, do you think narrow and tall is better than wider and shorter as it may condense the bubbles into a tighter space?


It's all the same in my opinion. It's just a relation between flow and CO2 bubble buoyancy. You could technically make a 1/2inch diameter reactor but then you would probably need to make a 5 meter tall or more reactor - lol
My opinion is the Rex Grigg is suited for medium to smaller tanks as it has a small foot print. The Cerges is better for bigger tanks. If you search google you will see that people with bigger tanks tend to use a Cerges type reactor. It's actually easier to make as you buy a clear water filter housing. Some people use a 20inches tall Cerges reactor.

Also something to consider, it's technically better to have the CO2 reactor on its own loop rather in line with your canister. This allow constant flow in time. If you put it in line with the filter, flow will progressively slow down as the filter gets clogged which introduces variations in Co2 injection through time. Most people do it this way though (myself included) because it's easier but it's not ideal.

Some litterature:


			How To Build A CO2 Reactor | Build a Regulator | Test Kit
		

Dual venturi DIY External CO2 reactor (last post on this thread is from me)








						DIY Inline reactor plans
					

the bubbling should stop after a few days




					www.aquaticplantcentral.com
				











						DIY Inline reactor plans
					

the bubbling should stop after a few days




					www.aquaticplantcentral.com


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## Hanuman (16 Feb 2021)

Zeus. said:


> Plus the slower the water in the chamber the higher the pressure the better a Venturi works


Well I think the venturi operating properly has more to do with the low pressure induced in the venturi port itself due to the restriction rather than in the chamber. In other words the CO2 is not being pushed to the venturi port but rather being sucked by the venturi port.


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## ForestDave (16 Feb 2021)

Cheers guys! 👍


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## Zeus. (16 Feb 2021)

Hanuman said:


> Well I think the venturi operating properly has more to do with the low pressure induced in the venturi port itself due to the restriction rather than in the chamber. In other words the CO2 is not being pushed to the venturi port but rather being sucked by the venturi port.



When we use a straw in a drink do we suck the water up or does atmospheric pressure push the water up the straw, the current accepted theory is atmospheric pressure pushes the water up. We just think we are sucking it up. 
In a ventri system its the pressure difference between the chamber and the ventri outlet that creates a force which pushes the water/air to the ventri outlet. The bigger the difference in pressure the better a ventri works, so a wider chamber generates more pressure so works better.


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## Hanuman (16 Feb 2021)

Zeus. said:


> When we use a straw in a drink do we suck the water up or does atmospheric pressure push the water up the straw, the current accepted theory is atmospheric pressure pushes the water up. We just think we are sucking it up.
> In a ventri system its the pressure difference between the chamber and the ventri outlet that creates a force which pushes the water/air to the ventri outlet. The bigger the difference in pressure the better a ventri works, so a wider chamber generates more pressure so works better.


It's not the flow in the chamber/reactor which resides long after the venturi port that causes the venturi to work. It's the pressure differential between before the venturi port and the venturi port itself (the fitting adapter in my case). You could have no reactor/chamber after the restriction that the venturi would still work the same and there would still be low pressure and a vacuum created that would force fluid/CO2 through the venturi port. In fact you need a minimum amount of velocity going through the restriction for the venturi to work else it doesn't.





As for the "sucking" it is pretty much the terminology used with venturi injectors  but yes it's the difference in pressure that causes it.


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## Zeus. (16 Feb 2021)

Hanuman said:


> It's not the flow in the chamber/reactor which resides long after the venturi port that causes the venturi to work. It's the pressure differential between before the venturi port and the venturi port itself (the fitting adapter in my case). You could have no reactor/chamber after the restriction that the venturi would still work the same and there would still be low pressure and a vacuum created that would force fluid/CO2 through the venturi port. In fact you need a minimum amount of velocity going through the restriction for the venturi to work else it doesn't.
> View attachment 163046
> 
> As for the "sucking" it is pretty much the terminology used with venturi injectors  but yes it's the difference in pressure that causes it.
> ...


Yes and No IMO, as if the pressure in the reactor chamber was less(or the same) than in the venturi port it would not work eg without flow (shut value at bottom of reactor), no flow no pressure difference. their is no pressure difference (aka suction) no venturi effect happens.

In a carburettor its the atmospheric pressure that pushes the fuel in, so IMO its the pressure in our CO2 reactor chamber that pushes the gas/water thought.



But yes 'suction' is a term used to described what what happens when their is a pressure difference.

Purley an academic debate , as long as it works


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## Franks (17 Feb 2021)

Simple question related to this.

Is there a Co2 reactor that is available to buy that works as intended and is far superior to using an in-tank or inline atomiser?

Thanks


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## Hanuman (17 Feb 2021)

A reactor is by definition more efficient than any diffuser. Now I would suggest reading the post #23 I made above


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## Franks (17 Feb 2021)

Yeah I get all the principles and understand the definition, but 'works as intended' suggests it's not prohibitive to buy, won't leak, won't work, won't incur a negative such as a large reduction in filter flow.

Reading the reviews of most manufacturers efforts suggest most people just end up with a headache when trying to use a reactor. I guess there isn't an off the shelf solution then?


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## Hanuman (17 Feb 2021)

Actually I know many who don't have problems and are happy with their reactors but I suspect those people have medium to small tanks. Regarding flow, there is no way around that. Any reactor will inevitably reduce the overall flow. That is why among other reasons serious people in the hobby have the reactor in a separate loop from the canister. 

There are off-the-shelf solutions, but as I stated above, one size does not fit all. That's simply because a reactor design is dependent on flow hence the reason why a large majority end up doing their own reactors. The best so far I have seen are those made by NilocG, but looking at their construction, anyone can do those at home.


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## Wookii (17 Feb 2021)

Franks said:


> . . .won't incur a negative such as a large reduction in filter flow.



I don't think there is any avoiding that one, that's just physics.


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## Hanuman (21 Feb 2021)

ForestDave said:


> Just found this tube connector. Would this work as a venturi or do you need the 1/4 CO2 pipe to stick out inside the larger pipe with the bevel facing away from the flow?
> 
> 
> 
> ...


Sorry I missed this post. I don't think it will work as this is a simple T-Joint and the opening inside is most probably flush with the diameter of the main connecter. What will happen is that water will simply shoot out of the smaller 1/4'', which in fact is what this T-joint was designed for. If you look at my pictures above the smaller connector is protruding inside the bigger connector and the face is cut to a 60 degree angle facing off the water current. That's how you create the venturi effect. In youtube you can find many people doing this at larger scales for aquaponics/hydroponics etc.


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## ForestDave (21 Feb 2021)

Thanks @Hanuman 
👍


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## zozo (21 Feb 2021)

Zeus. said:


> Although with second thoughts the fitting is the constriction so *Yes* it should work


Indeed it might...  You can also DIY one that might do better. With this, I tested it a few years back as an air venturi and worked a charm.





You can drill a very small hole in the hexagonal nut say 1mm or even smaller if you want. Then what i yet have not tested but in theory, it should do even better. Drill this hole in an incline in the flow direction. Than take a larger drill in 4.2mm and drill a 5mm deep hole at 90° on top of the 1mm declined hole. The Hex nut has enough material to it for that. Tape M5 thread in this 4.2mm hole and screw in another 4mmxM5 hose pilar. I used one like this with a O-ring and a clamp nut.



Or use one like this with a drop of Locktite or other sealant on the thread.




And this goes again on the other end with a rubber washer.





It is 10mm internal diameter, which makes it 2mm reduction in a 16/12mm hose.  And the 1mm inlet gives a finer bubble. 
But as said I didn't test it with an inclined 1mm hole, I drilled it straight and it already worked well as a venturi inlet. Later I thought I should have tried to drill it inclined. with the flow direction. There was nothing to lose to do that anyway. (Well other than snapping a drill if you are not careful.)


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## ForestDave (21 Feb 2021)

@Hanuman
Could you explain the purge valve please? Is that a simple ball valve adjusting the flow to the Venturi?
Also you have two other green valves and pipes going into the reactor, is that for fertiliser?
Thanks
Dave.


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## ForestDave (21 Feb 2021)

zozo said:


> Indeed it might...  You can also DIY one that might do better. With this, I tested it a few years back as an air venturi and worked a charm.
> 
> View attachment 163345
> 
> ...


Sounds like a neat solution Zozo. Some skilful drilling too.


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## zozo (21 Feb 2021)

ForestDave said:


> Sounds like a neat solution Zozo. Some skilful drilling too.



It's a relatively soft plastic, that's a huge plus...  But you do need to correct tap, the machine tap is pointed and the hand tap is blunt with a flat end. The latter one is needed for blind holes.


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## ForestDave (21 Feb 2021)

zozo said:


> It's a relatively soft plastic, that's a huge plus...  But you do need to correct tap, the machine tap is pointed and the hand tap is blunt with a flat end. The latter one is needed for blind holes.


Cheers. I was wondering about that bit as I’ve only used machine taps before. I’ll look up the hand tappers.


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## Zeus. (21 Feb 2021)

ForestDave said:


> Could you explain the purge valve please?


Just a way of venting air (and CO2) after maintenance/fitting, just makes life easier. I just release the air by loosening the pipe fittings to my APS EF2 after maintenance.
I haven't clean my reactors in years, as when I did do them they was basically clean.


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## zozo (21 Feb 2021)

ForestDave said:


> Cheers. I was wondering about that bit as I’ve only used machine taps before. I’ll look up the hand tappers.



I believe the correct term is Blind Hole Tap, no idea actually if they come in a machine tap version. In the regular hardware store in only see machine taps that are pointed for easier guiding. And then the 3 piece set hand taps that are suitable for blind holes ad need the 3 stages for proper guidance.

But in plastic-like PVC this is peanuts, only used tap number 1, and it's already ok to screw something metal in and fit snuggly.


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## Hanuman (21 Feb 2021)

ForestDave said:


> @Hanuman
> Could you explain the purge valve please? Is that a simple ball valve adjusting the flow to the Venturi?
> Also you have two other green valves and pipes going into the reactor, is that for fertiliser?
> Thanks
> Dave.


Yes that's an irrigation valve and indeed it's to adjust the flow but in reality it is more to fully close it when doing maintenance. There is no real need to regulate the flow purge valve going to the venturi port. I leave it fully open.



ForestDave said:


> Also you have two other green valves and pipes going into the reactor, is that for fertiliser?


Never thought of using that for fertilizer but you gave me an idea lol
Those are 2 additional purge ports at different depth levels. If you notice the tubbing goes deeper for each. This was done at the design level in case I wanted to use different purge levels when putting the reactor in service since I wouldn't be able to open the reactor again once glued. So far I have only used the same one with the blue valve.


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## ForestDave (21 Feb 2021)

Hanuman said:


> Yes that's an irrigation valve and indeed it's to adjust the flow but in reality it is more to fully close it when doing maintenance. There is no real need to regulate the flow purge valve going to the venturi port. I leave it fully open.
> 
> 
> Never thought of using that for fertilizer but you gave me an idea lol
> Those are 2 additional purge ports at different depth levels. If you notice the tubbing goes deeper for each. This was done at the design level in case I wanted to use different purge levels when putting the reactor in service since I wouldn't be able to open the reactor again once glued. So far I have only used the same one with the blue valve.


Good stuff, thank you.
When the dust has settled from my new tank build and I'm feeling flush I'll find someone who wants to go halves on a clear pvc tube as they seem to only come in 1 - 1.2m lengths.
Cheers 
Dave.


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## ForestDave (10 Mar 2021)

Well, I know that clear plastic is the best for setting up a reactor, but as I had a few unused lengths of 110mm soil pipe in the garage I thought I'd try a wide version of Hanumans design as I didn't have enough height under my tank to make his recommended 60cm reactor. I'm on day 2 with it and it's not working that well yet. The venturi isn't kicking in. I added a bit of tubing inside the venturi hose joiner this morning, on the feed side to increase the restriction and lower the pressure. This hasn't helped no matter how much I adjust the flow. Now I'm wishing I'd held out for the clear pipe!  I also changed the CO2 feed pipe length this morning so that it produced the bubbles low down in the reactor as I saw Tom Barr's did this. This CO2 feed pipe was also stretched to form a taper and give smaller bubbles. The internal venturi feeding pipe has also been bent to the edge of the reactor as I saw Hanuman's looked to be favoring the edge and yesterday it was right next to the water feed pipe which I was worried might be interfering with it.
Either way, it's semi-working. After 3.5hrs the D/C is at between 12 and 20ppm at about 6bps on the CO2 Art regulator. The Reactor seems heavy so there is plenty of water in there and not just a vat of CO2. I need to re-do the venturi though as it's just not pulling anything through and at that bubble rate it would have been nice to be lime green by now. 
I'll stick some photos up from my phone in a minute. 
Any tips welcome!!


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## ForestDave (10 Mar 2021)




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## ForestDave (10 Mar 2021)

Few more images


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## ForestDave (10 Mar 2021)

The Venturi


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## Zeus. (10 Mar 2021)

I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor



plus have a value outside to vent the reactor of air on first use.

The fact you have a pH drop means its doing something 
Is the tank bubble free?
Noise levels of reactor?


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## ForestDave (10 Mar 2021)

Zeus. said:


> I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor
> View attachment 164546
> plus have a value outside to vent the reactor of air on first use.
> 
> ...


Thanks Zeus. 
I’ll give that a go for tomorrow. I’ve been isolating the reactor feed and sending the whole flow from the FX6 through it for 5-10 seconds once or twice hoping that would flush any trapped gas.  A purge pipe makes sense though. I was going to weigh it tomorrow before start up so I could gauge how much gas is in there. 
Putting an ear to it when in use you can get a sense of how much flow is going through it. Not ideal but I suppose I just need to be methodical with any changes. 
When the D/C got to lime green it’s stayed nice and constant all day and    there have been hardly any bubbles. Some of the few bubbles have been from slight pearling. So the tank is looking nicer!! There’s a gentle trickling sound from the reactor which is fine. I just need it to get to 20ppm a bit quicker.


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## Zeus. (10 Mar 2021)

ForestDave said:


> I just need it to get to 20ppm a bit quicker.



Without duel solenoids on the CO2 reg there are limits, my fastest was 20mins for 1.3pH drop with my 500litre setup with duel solenoids/injection, but an hour to three hours is about normal with single solenoid with bigger tanks taking longer. My 50l with single solenoid/injection takes about 2.5 hours


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## ForestDave (10 Mar 2021)

Zeus. said:


> Without duel solenoids on the CO2 reg there are limits, my fastest was 20mins for 1.3pH drop with my 500litre setup with duel solenoids/injection, but an hour to three hours is about normal with single solenoid with bigger tanks taking longer. My 50l with single solenoid/injection takes about 2.5 hours


Cheers. That's good to know. Do you have one solenoid pump a load of CO2 in quickly and then turn off while the other keeps going and maintains the level you're after? 20mins is pretty phenomenal for a 500L tank!!


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## Zeus. (10 Mar 2021)

ForestDave said:


> Do you have one solenoid pump a load of CO2 in quickly and then turn off while the other keeps going and maintains the level you're after?


Yep, the needle valve fully open then off at lights on

I do use a PLC to control them, wouldn't trust a normal timer as with such a high initial injection rate it could soon be very bad for livestock.


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## Hanuman (11 Mar 2021)

Zeus. said:


> I would have the the venturi feed pipe shorter (short as possible) within the reactor - then air pocket will be less at top of reactor


No you don't want that. You want the CO2 to partially build up in the reactor. That's what makes the mixing more efficient. The bleed/venturi port is to prevent a back pressure, usually after several hours of injections. That's why Tom Barr suggests you building bleed ports at different heights so that one can adjust the preferred level after you put your reactor in operation. It's difficult to judge what level is better as all setups/water flow are different. If you cut the tubbing short as you suggest you will have CO2 being sucked in pretty quick after start of injection and potentially start creating smaller bubbles, which definitely you don't want.


Zeus. said:


> plus have a value outside to vent the reactor of air on first use.


Yes definitely. This is a must if you don't want to be scratching your head why your filter is not working if you stop it and start it again and for some reason there is CO2 or excess air in the reactor, specially in the first run.


ForestDave said:


> The venturi isn't kicking in.





ForestDave said:


> The internal venturi feeding pipe has also been bent to the edge of the reactor as I saw Hanuman's looked to be favoring the edge and yesterday it was right next to the water feed pipe which I was worried might be interfering with it.


No I didn't favor the edge. I just didn't have straight rigid PVC tubbing LOL. But it doesn't matter if it's at the edge or not. The important is the level. Once Co2 reaches that level then the venturi quicks in.

I am also noticing a small flaw in your reactor that makes your reactor less efficient. The top part is recessed a good ~1cm or maybe less compared to where the water arrives. This has the consequence of having CO2 accumulate in the top part of the reactor sitting doing nothing before water is actually hitting CO2. You want to have that black part at least flush with the grey part. Another more efficient way would be to build a small cone like structure inside the reactor that forces the CO2 directly below the water stream arriving from the top. That way you immediately and forcibly push CO2 to mix with the incoming water. You will see dramatic improvement.


ForestDave said:


> I need to re-do the venturi though as it's just not pulling anything through and at that bubble rate it would have been nice to be lime green by now.


You need to make sure the small part inside the bigger hose connecter is cut to ~60 degree angle and that the face of the angle is facing away from the current. Make the hole as small as possible in the small tubbing connecter. In fact I melted that small connector to seal the hole and then used a needle which I heat it up and reformed a smaller hole. I had to do that part 3 times before I was satisfied with it.



ForestDave said:


> After 3.5hrs the D/C is at between 12 and 20ppm at about 6bps on the CO2 Art regulator.


Not sur what your tank size is but I have 180L raw tank. Net volume maybe ~100L or so. I am pumping a constant stream of CO2. I can't count the bubbles so 6bbs for 12/20ppm CO2 actually doesn't look bad. Just make the small mods above and you should be golden just like my drop checker...😙


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## Hanuman (11 Mar 2021)

Noticed additional things. Your CO2 working pressure is below 20 PSI. I would increase that to 20 PSI. The more the CO2 builds up in the reactor and the more back pressure you will have. Considering you are using a CO2Art regulator which has a mediocre needle valve (no, sorry, a poorly constructed needle valve.... no, sorry again, let's be straight here, a nail), your CO2 will not be constant and I can guarantee that your CO2 will fluctuate during the day. Even without the back pressure, those Co2Art needle valves are pretty unstable. That's a known fact. I've been there.

Here is what a "needle valve" from Co2Art looks like... I will let you judge:


 

 



Here is a considerable improvement 😇:




And here is a Royal improvement, I will leave the details for another thread though. Don't want to derail things here but just to give some context on why Regs and needle valves are important:


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## ForestDave (11 Mar 2021)

Thanks, @Hanuman.  I'll get to work!
The small pipe inside the venturi was beveled to at least 60 degrees and faced away from the flow but I didn't adjust the hole size. When I initially turned it on, the water went down the pipe the wrong way. I'll re-do it. 👍 Would angling the pipe 20-30 degrees in the direction of the flow also help?

I did have the regulator set at 30 PSI for the inline diffuser but reduced it two days ago as I felt that was too high and meant fine adjustments to the flow were really hard to do, I'll whack it up to 20 PSI. Sounds like the regulator might have something to do with tricky adjustments also. I'd be really interested to see your post on regulator needle valves.  
Thank you for the tips!!


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## ForestDave (11 Mar 2021)

Zeus. said:


> Yep, the needle valve fully open then off at lights on
> 
> I do use a PLC to control them, wouldn't trust a normal timer as with such a high initial injection rate it could soon be very bad for livestock.



Cheers Zeus.
So is it better for the plants and livestock to get to the desired CO2 PPM as quickly as possible or does it save on gas?

 I'm going to have to look into the whole PLC business. I'm about to set up some fert dosers controlled by a Meross wifi power strip. They seem really solid and you don't need to re-adjust anything after a power cut, (of which we have many where I live, I think it's all the trees falling on cables). The only times I've had issues are always from human error, me pressing the wrong thing, or forgetting to save an alteration. My plan is to set the doser times twice for each dose on their own power strip and then never touch it! 
PLCs sound like the future though!


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## Hanuman (11 Mar 2021)

ForestDave said:


> So is it better for the plants and livestock to get to the desired CO2 PPM as quickly as possible or does it save on gas?


CO2 only serves plants, not fish. The reason you want to have your CO2 levels at optimal levels within the first hour or two is because once lights turn on, plants will start consuming CO2 fast. In fact the first hours of photosynthesis are the ones where the plant consumes the most CO2 if I am not mistaken. If your CO2 is not optimal at that moment you will see a big dip in CO2 concentration in your water colum which will then take time to recover. You don't want that.
Read this < Surface agitation & gaseous exchange in CO2 injected tanks >, you will thank me later. 🙏


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## Zeus. (11 Mar 2021)

ForestDave said:


> So is it better for the plants and livestock to get to the desired CO2 PPM as quickly as possible or does it save on gas?


Technically it should save gas as the CO2 is on for shorter time, however the major advantage is on WC day you have more time before the CO2 comes on to fit your WC in, as once the CO2 is on you dont want to start a WC

PLC are great IMO but not cheap, @ian_m did a great piece of coding for the LogoSoftComfort, 'TankyMyTank' which does all the times for lights/CO2 on/off so once setup you set one time 'lights on' and 'Lights off' everything else adjusts its on/off times. So if running late with WC I just the on time of lights and everything adjusts to suit, then if you finished sooner than planned , adjust on time and done again. Again a shorter pH drop time helps here to and after a WC with the dissolved CO2 in tap water you get the pH drop faster again, did use a pH controller for some time to control/monitor this. Power cut no problem. Plus was fun to make and do the software design. You can download the demo and practice your software design and then use it 'if' you do get a PLC - I did. Helps if you have ethernet port close to tank, can access/adjust PLC from PC or laptop over LAN, Have used phone also to access the webadmin for PLC, not keen using phone as screen to small IMO.


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## Zeus. (11 Mar 2021)

Hanuman said:


> No you don't want that. You want the CO2 to partially build up in the reactor. That's what makes the mixing more efficient. The bleed/venturi port is to prevent a back pressure, usually after several hours of injections. That's why Tom Barr suggests you building bleed ports at different heights so that one can adjust the preferred level after you put your reactor in operation. It's difficult to judge what level is better as all setups/water flow are different. If you cut the tubbing short as you suggest you will have CO2 being sucked in pretty quick after start of injection and potentially start creating smaller bubbles, which definitely you don't want.


I have limited experience with venturi, so I would listen to those that have made them and got them working  trying/sharing my own ideas at the same time.


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## Hanuman (11 Mar 2021)

I mean you can have the bleed tube that is nearly flush to the top like you suggested but the idea behind that bleed valve going to the venturi port is to reduce the back pressure once it builds up to a certain point. It wouldn't do harm the way you suggested but if the reactor is undersized or there is too much flow then small bubbles will start escaping the reactor because the venturi port is shredding the CO2 into smaller bubbles.


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## Angelfishguy99 (14 Mar 2021)

Magoo said:


> I'm currently using the Qanvee inline CO2 diffuser. It works well enough but the bubbles it generates is becoming tiresome to look at. I'm planning to shift to an external reactor but I just don't have the inclination or time to source the parts for a DIY project. Has anybody try this reactor? What are your thoughts?
> 
> 
> 
> ...



Has anyone tried this reactor? Fizzy water is slowly starting to get to me


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## Magoo (15 Mar 2021)

Angelfishguy99 said:


> Has anyone tried this reactor? Fizzy water is slowly starting to get to me



 It seems there isn't much difference, in terms of the fizzy water, from the Qanvee inline. I have the reactor on hand but haven't installed it yet.


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## foxfish (15 Mar 2021)

My inbuilt glossary of terms suggests you guys are calling an ‘atomiser’ a reactor.
Atomisers purposely produce micro bubbles, reactors dissolve the bubbles.


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## Angelfishguy99 (15 Mar 2021)

foxfish said:


> My inbuilt glossary of terms suggests you guys are calling an ‘atomiser’ a reactor.
> Atomisers purposely produce micro bubbles, reactors dissolve the bubbles.


Yeah i have an atomizer and am sick of the bubbles so i was asking to see if anyone has tried the reactor that the OP posted about cause if it was any good i think i would get one


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## Angelfishguy99 (15 Mar 2021)

Magoo said:


> It seems there isn't much difference, in terms of the fizzy water, from the Qanvee inline. I have the reactor on hand but haven't installed it yet.


Looking forward to hearing your thoughts on it


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## Magoo (16 Mar 2021)

foxfish said:


> My inbuilt glossary of terms suggests you guys are calling an ‘atomiser’ a reactor.
> Atomisers purposely produce micro bubbles, reactors dissolve the bubbles.


I misunderstood Angelfishguy's statement. I thought he was already using the reactor and still had the 'fizzy' water.


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## ForestDave (16 Mar 2021)

Hanuman said:


> CO2 only serves plants, not fish. The reason you want to have your CO2 levels at optimal levels within the first hour or two is because once lights turn on, plants will start consuming CO2 fast. In fact the first hours of photosynthesis are the ones where the plant consumes the most CO2 if I am not mistaken. If your CO2 is not optimal at that moment you will see a big dip in CO2 concentration in your water colum which will then take time to recover. You don't want that.
> Read this < Surface agitation & gaseous exchange in CO2 injected tanks >, you will thank me later. 🙏


Cheers Hanuman. 
Good article and link to the article on CO2 diffusion. I never realised plants could access more CO2 from misting. Could be useful for the first hour or two when the plants need it most. 
My inverse cone adapter for my reactor is coming on. I’ve formed it with a straight cone from the edge of the pipe directly to the central water inlet pipe. Before I tidy it up and fibreglass it up would any sort of wider pocket near the inlet pipe be advantageous in your view? 
Thanks 
Dave.


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## ForestDave (16 Mar 2021)

Sorry can’t seem to load the internal shot. Will try again.


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## ForestDave (16 Mar 2021)

Hopefully this loads.


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## Hanuman (16 Mar 2021)

ForestDave said:


> would any sort of wider pocket near the inlet pipe be advantageous in your view?


Not sure I understand. Care to explicit that?


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## ForestDave (16 Mar 2021)

Hanuman said:


> Not sure I understand. Care to explicit that?


Would a wider gas pocket be useful near the water inlet pipe? At the moment all the gas is funnelled straight into the inlet water. I suppose you never really know until you test it as it the flow level varies.


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## Hanuman (16 Mar 2021)

Ok got it. I think that's fine. The narrower the better I would say. The idea is that CO2 congregates just below where the water is arriving.


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## ForestDave (16 Mar 2021)

Thanks!


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## Wookii (19 Mar 2021)

Hanuman said:


> Noticed additional things. Your CO2 working pressure is below 20 PSI. I would increase that to 20 PSI. The more the CO2 builds up in the reactor and the more back pressure you will have. Considering you are using a CO2Art regulator which has a mediocre needle valve (no, sorry, a poorly constructed needle valve.... no, sorry again, let's be straight here, a nail), your CO2 will not be constant and I can guarantee that your CO2 will fluctuate during the day. Even without the back pressure, those Co2Art needle valves are pretty unstable. That's a known fact. I've been there.
> 
> Here is what a "needle valve" from Co2Art looks like... I will let you judge:
> View attachment 164603 View attachment 164605 View attachment 164606
> ...


 I'd like to know the needle valve details, and reg mods you've made please @Hanuman - please tag me if you start a new thread on it.


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## Zeus. (8 Aug 2021)

Got round to making my venturi, lucky for my @Andrew Butler gave me loads of fittings (many thanks again Andrew) which did the trick 1/2 bit of tubing and fittings from 1/2 inch thread to 20mm connectors drilled a 6.5mm hole and a dab of solvent cement. 



Think the 6mm push fit adaptor will work well, filed a little chamfer to one side of adaptor/venturi inlet








Need a few 25mm fittings and should be good to go


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## Zeus. (13 Aug 2021)

Zeus. said:


> Got round to making my venturi, lucky for my @Andrew Butler gave me loads of fittings (many thanks again Andrew) which did the trick 1/2 bit of tubing and fittings from 1/2 inch thread to 20mm connectors drilled a 6.5mm hole and a dab of solvent cement.
> View attachment 172924
> Think the 6mm push fit adaptor will work well, filed a little chamfer to one side of adaptor/venturi inlet
> View attachment 172925
> ...


Turns out Scotty from 'Star Trex' was right - 'you cani change the the laws of physics'. Which was what I was trying to do as I hadn't done my homework 😅





My throat was well in excess of the internal diameter of the pipe !!

However feeding the twin CO2 injection into single venturi worked well without having to inject into the reactors, needs some balancing as one reactor was getting the lions share of the CO2 bubbles from venturi inlet and it also with the aid of a 'tee' made it very easy to bleed the reactor as well, ordered a few bits and will see how it goes.


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