# CO2 Reactor for small tank..which ones?



## MMonis (16 Feb 2022)

I am thinking of switching to an external CO2 reactor, as my existing NEO intank diffuser has started sending out larger bubbles even after the bleach cleaning method.  This is also causing my external canister filter to burp often as the diffuser is close to the intake of the filter.
Also a lot of CO2 bubbles are escaping directly to the surface.

Now I just have a 15 gallon planted tank equipped with an Oase Biomaster 250 Thermo filter with output as a spray bar.  Need some advice as to which external CO2 reactors would suffice for this aquarium size ?
I came across a few listed here:

Yidao external CO2 reactor on ali express (cheapest incl. delivery to Denmark)
JDAquatec.de Mini Co2 Reactor on amazon
Ista Max Mix Co2 reactor
Would it be an overkill if I switch to an external CO2 reactor instead of the intank diffuser and would you have any other suggestions than the list above ?

Regards,
Mel


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## Wookii (16 Feb 2022)

MMonis said:


> I am thinking of switching to an external CO2 reactor, as my existing NEO intank diffuser has started sending out larger bubbles even after the bleach cleaning method.  This is also causing my external canister filter to burp often as the diffuser is close to the intake of the filter.
> Also a lot of CO2 bubbles are escaping directly to the surface.
> 
> Now I just have a 15 gallon planted tank equipped with an Oase Biomaster 250 Thermo filter with output as a spray bar.  Need some advice as to which external CO2 reactors would suffice for this aquarium size ?
> ...



All of them would likely do the job on a 60 litre tank as your injection rate will be much lower than the maximum they can handle.

They likely all have their issues - the first has been tested by several people on this forum in the thread you’ve probably already read. On the third there are plenty of reports on the web about, some say the plastic is very brittle and breaks, other complain of noise.

The second remains untested on here as far as I am aware, but given it’s diminutive size, and your likely injection rate, might well be perfect for your setup.


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## MMonis (16 Feb 2022)

Wookii said:


> All of them would likely do the job on a 60 litre tank as your injection rate will be much lower than the maximum they can handle.
> 
> They likely all have their issues - the first has been tested by several people on this forum in the thread you’ve probably already read. On the third there are plenty of reports on the web about, some say the plastic is very brittle and breaks, other complain of noise.
> 
> The second remains untested on here as far as I am aware, but given it’s diminutive size, and your likely injection rate, might well be perfect for your setup.


For the first one, can it be used out of the box or is it necessary to mod it in some way ? I read the thread which had this info but then was completely lost on what the final outcome was, considering my noob skills in this area


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## Wookii (16 Feb 2022)

MMonis said:


> For the first one, can it be used out of the box or is it necessary to mod it in some way ? I read the thread which had this info but then was completely lost on what the final outcome was, considering my noob skills in this area



Yeah, it can be used ‘as-is’ out of the box - that’s not to say it can’t be improved with a bit of tweaking, like most things, but that’s not essential.


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## arcturus (16 Feb 2022)

Hi! I actually have the JDAquatec reactor, Maxi version with 16mm pipes. I used it on my previous 120P tank with an Oase BioMaster 600. This reactor is quite compact (see picture) and very solid. I was able to get full CO2 dissolution if one keeps the flow at a medium/low rate. Note that I had the reactor on a filter bypass. According to the table of the manufacturer below I should have been running it at a flow rate of 300-400 l/h (never actually measured it). The reactor managed to achieve full dissolution even if I skipped the bypass altogether, but then burped a couple of CO2 bubbles every few minutes. If you have any questions about this reactor just ask. I used it for nearly 2 years with zero issues. 

In case you decide for this model I would suggest you get the Midi version so that you connect it directly to the 16mm pipes of the Oase  (the Mini version uses 12mm pipes). You may also need a bypass. In the past, this manufacturer was selling a version with integrated bypass. If it is not available anymore then you can build one easily.


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## hypnogogia (16 Feb 2022)

arcturus said:


> I used it for nearly 2 years with zero issues.


That’s good to hear, as I’m considering investing in one.  Just need to find a way to get hold of it in the UK, now that brexit has made these things more difficult.


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## Sdogg (16 Feb 2022)

I'm currently testing the JD aquatec midi 16mm reactor with integrated bypass.

Started using it about 2 weeks ago. Mixed opinion so far. It's great not having any mist, but I was expecting to use less co2 due to reactors being more efficient, however I'm not finding this. My tank is 125l with biomaster 600.

To achieve the same pH drop I was achieving before with an in-line diffuser, I've actually had to keep the injection rate the same. I can always hear a trickling noise. It accumulates a lot of gas, I've fiddled endlessly with the bypass to tune it - open it wide and the gas escapes straight out the top of the chamber into the tank. I've found it best just to keep the bypass closed. I have to purge it daily by opening the bypass.

It's a compact unit, neat and well made. Perhaps I should have got the maxi? I'm currently waiting for the yidao reactor to arrive from AliExpress, we'll see how I fare with that....


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## Wookii (16 Feb 2022)

hypnogogia said:


> That’s good to hear, as I’m considering investing in one.  Just need to find a way to get hold of it in the UK, now that brexit has made these things more difficult.



I’ve ordered one from Amazon.de 😉


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## arcturus (16 Feb 2022)

hypnogogia said:


> That’s good to hear, as I’m considering investing in one.  Just need to find a way to get hold of it in the UK, now that brexit has made these things more difficult.





Sdogg said:


> I'm currently testing the JD aquatec midi 16mm reactor with integrated bypass.
> 
> Started using it about 2 weeks ago. Mixed opinion so far. It's great not having any mist, but I was expecting to use less co2 due to reactors being more efficient, however I'm not finding this. My tank is 125l with biomaster 600.
> 
> To achieve the same pH drop I was achieving before with an in-line diffuser, I've actually had to keep the injection rate the same. I can always hear a trickling noise. It accumulates a lot of gas, I've fiddled endlessly with the bypass to tune it - open it wide and the gas escapes straight out the top of the chamber into the tank. I've found it best just to keep the bypass closed. I have to purge it daily by opening the bypass.


Interesting. I don't have that issue, but I have the Maxi, also with a Biomaster 600. What I experienced when I skipped the bypass is that there were some large CO2 bubbles coming out of the reactor once in a while - meaning there was CO2 accumulation inside the reactor. But at lower flow rates, there was no CO2 accumulation and I could only hear the reactor at a very close distance. Ah! Note that I built the bypass myself and have a valve controlling the water flow into the reactor (the optional bypass that ships with this reactor has no valve on the reactor inlet but on the other water line). So, I was probably running the filter at a low flow rate, and therefore maximising the dissolution.


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## MMonis (17 Feb 2022)

I contacted the manufacturer of JD Aquatec and he recommended the 16mm fixed bypass with midi reactor costing around 74 eur. Delivery cost is another 15 eur within the EU.


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## Wookii (17 Feb 2022)

hypnogogia said:


> That’s good to hear, as I’m considering investing in one.  Just need to find a way to get hold of it in the UK, now that brexit has made these things more difficult.





Wookii said:


> I’ve ordered one from Amazon.de 😉



Scratch that - my order got cancelled!


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## MMonis (17 Feb 2022)

Wookii said:


> Scratch that - my order got cancelled!


Maybe you should write to them directly as they also ship orders outside of amazon and ebay.


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## Wookii (17 Feb 2022)

MMonis said:


> Maybe you should write to them directly as they also ship orders outside of amazon and ebay.



Thanks, yeah I have, I got in touch with Jörg Düren directly through the website - he replied straight away. Shipping to the UK is 29.99 EURO. He said he had to cancel the Amazon.de order because the shipping is only set up for Germany at 14.99 EURO, so I will order directly from him instead.


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## hypnogogia (17 Feb 2022)

Wookii said:


> Thanks, yeah I have, I got in touch with Jörg Düren directly through the website - he replied straight away. Shipping to the UK is 29.99 EURO. He said he had to cancel the Amazon.de order because the shipping is only set up for Germany at 14.99 EURO, so I will order directly from him instead.


Shame it got cancelled, but great that he is so accommodating.  So in total it will be about £86.  Let us know how you get on with it.  So far I've only seen generally positive reviews, with a few saying they get a few bubbles coming through.


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## Wookii (17 Feb 2022)

hypnogogia said:


> Shame it got cancelled, but great that he is so accommodating.  So in total it will be about £86.  Let us know how you get on with it.  So far I've only seen generally positive reviews, with a few saying they get a few bubbles coming through.



I went for the Midi with the bypass fitted and mounting bracket which was 103.99 Euro delivered, and came to about £94 via Paypal. Hopefully it will work well - I plan to use it on my forthcoming 1500 which will have a sump, and this form factor will fit nicely inside the sump.


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## Rasmusm (20 Feb 2022)

Hi all
I just installed the midi version yesterday with a bypass on my 576l tank with 112l sump. 
Previously had the co2art bazooka which was doing a good job 3bps was enough to go from 7.5ph to 6.9, green on the drop checker with 20 ppm fluid in.

The reactor is driven by a Eheim compact 600l/h small pump, bypass closed all the way, same pump feeds my eheim reeflex 800 UV light (On same loop). It's quite impressive actually, but ph rise to ~7.05, so now i'm trying 3.5bps, to see if I can get it back down there.
I do hear occasionally hear it burping and venting out a lot of co2, but its ok at least i don't have to look at all the micro bubbles anymore.
In my case I think it's not as effective as the bazooka diffuser, but I wonder if I install a 1000l/h eheim compact instead, it might be more effective not sure, my UV is rated for max 600l/h for killing off microbes so I probably wont to that.
Let me know if you want a small video

/Rasmus


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## hypnogogia (20 Feb 2022)

Depending on the hose size you’re using, 600l/h might be too high, which would explain the occasional burping.


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## Rasmusm (20 Feb 2022)

I see, yea running 12/16mm hose, will leave it as is. Just feels weird its less effective than diffuser


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## Wookii (20 Feb 2022)

I was told that the Midi needs 350lph to operate effectively, so you might want to try opening the bypass to reduce the flow through it?


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## hypnogogia (20 Feb 2022)

Here’s the information for flow rates.


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## MMonis (16 Feb 2022)

I am thinking of switching to an external CO2 reactor, as my existing NEO intank diffuser has started sending out larger bubbles even after the bleach cleaning method.  This is also causing my external canister filter to burp often as the diffuser is close to the intake of the filter.
Also a lot of CO2 bubbles are escaping directly to the surface.

Now I just have a 15 gallon planted tank equipped with an Oase Biomaster 250 Thermo filter with output as a spray bar.  Need some advice as to which external CO2 reactors would suffice for this aquarium size ?
I came across a few listed here:

Yidao external CO2 reactor on ali express (cheapest incl. delivery to Denmark)
JDAquatec.de Mini Co2 Reactor on amazon
Ista Max Mix Co2 reactor
Would it be an overkill if I switch to an external CO2 reactor instead of the intank diffuser and would you have any other suggestions than the list above ?

Regards,
Mel


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## Rasmusm (20 Feb 2022)

Thanks,  will try to open it a bit 
I have now opened bypass 10-15°, will give it a couple of days to settle in


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## Wookii (20 Feb 2022)

Rasmusm said:


> Thanks,  will try to open it a bit
> I have now opened bypass 10-15°, will give it a couple of days to settle in



Let us know if it stops the burping/bubbles being pushed out.


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## Sdogg (20 Feb 2022)

Rasmusm said:


> Thanks,  will try to open it a bit
> I have now opened bypass 10-15°, will give it a couple of days to settle in


I've tried different bypass positions, giving it a day each time to settle.
You may get less noise with a more open position but the pH drop rate becomes much slower, to the point where would probably take about 4hrs in my setup.
Opening the bypass fully results in the bubbles escaping straight out the top of the chamber, you can hear it doing this.
The best compromise I found is to fully close the bypass, high injection rate. I get 1.2ph drop in 3 hrs - was expecting a lot better for a reactor, especially one that is so highly praised in the promotional material.
After the photoperiod you can hear the accumulated gas so I have to purge it by opening the bypass and allowing the gas to escape out the top of the chamber.
Only thing maybe I should have done is get the maxi? Only benefit over an in line is no mist. 
Still find it shocking there isn't an off the shelf reactor that "just works" without issue or the need to yeehaa modify


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## MMonis (20 Feb 2022)

I am thinking to go with the Yidao CO2 reactor instead of the Midi as the cost of the midi is almost 3.5 times the cost of yidao. And since I just have a 54  litre tank I am guessing the yidao  should be sufficient.

Would it be a problem of surface agitation with my Oase Biomaster 250 which is rated 900 l/h and my outflow being a spray bar if I setup the Yidao co2 reactor ?


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## Rasmusm (21 Feb 2022)

Hi Sdogg, yea after opening the bypass a bit, my pH actually raised. Now im at 1bps more than my diffuser, thought I was gonna save on Co2 with this reactor hmm


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## Rasmusm (22 Feb 2022)

Update on the reactor, hmm not really happy about it... 4.5bps 1.5bps more than with my co2art diffuser. And yet pH is still 0.2 higher than with diffuser. Using 50% more co2  to get less of pH drop just feels weird


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## Wookii (22 Feb 2022)

Rasmusm said:


> Update on the reactor, hmm not really happy about it... 4.5bps 1.5bps more than with my co2art diffuser. And yet pH is still 0.2 higher than with diffuser. Using 50% more co2  to get less of pH drop just feels weird



Oh that is surprising to hear, are you still getting loads of gas burping out of it then?


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## Rasmusm (22 Feb 2022)

Only if I shut off the valve completely will it burp out gass every now and then. But slightly open it doesnt do that   I dont quite get why my ph is higher hmm. If we assume it dissovles 100% then should be better than a diffuser, and the 3bps I was running on diffuser should be more than enough


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## Wookii (22 Feb 2022)

Rasmusm said:


> Only if I shut off the valve completely will it burp out gass every now and then. But slightly open it doesnt do that   I dont quite get why my ph is higher hmm. If we assume it dissovles 100% then should be better than a diffuser, and the 3bps I was running on diffuser should be more than enough



Yeah, that was my thinking, if all the gas is being dissolved and you're getting no significant bubbles, it should be dissolving more CO2 than your diffuser. How are you measuring the pH drop - just checking you are hitting the same minimum pH as previously?

Perhaps its worth checking you haven't got any leaks on the reactor or CO2 line since you changed over?


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## Rasmusm (22 Feb 2022)

I measure ph with my tds pen, same spot daily. I can place the probe in my overflow chamber and leave for a few minutes for the probe to stabilize.

I contacted the guy in Germany, He told me to measure pH in my sump with the diffuser and then with the reactor.

Obviously the micro bubbles from the diffuser are getting sucked in through my return pump and up in the tank.
But the reactor is on a closed loop in the sump aswell, so should equally be sucked up into the tank. More testing is needed   just affraid of bba eventually...


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## MMonis (26 Mar 2022)

So I scrapped the idea of getting a CO2 reactor and instead purchased a CO2art Inline diffuser. How soon can you start doing a pH profile for optimizing CO2 after installing a new inline diffuser ?


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