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Sera CO2 reactor 500

S

Smykel

New Member
Joined
9 Mar 2023
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4
Location
Wielka Brytania
Hi all

Recently I decided to swap the CO2 diffuser for a reactor. To make possible the highest water flow I set it on a Fluval e307 filter. According to the manual, it required a minimum of 500l/h water flow. According to filter manual, it provides a water flow of around 780l/h. I can clearly see the rotating part breaks bubbles. Unfortunately, my CO2 indicator is still blue. Did anyone have a similar problem? I don't think so I will have to fit the biggest possible Fluval filter to run only this reactor.
 
Yes, about 3-4 bubbles per sec. I thought that with reactor I can use less of co2 as it's diffused co2 in 100%.
 
I was wondering if it could be an good idea to fit inline diffuser before reactor so reactor will have smaller bubbles to break to dissolve in water.
 
Smykel said:
Yes, about 3-4 bubbles per sec. I thought that with reactor I can use less of co2 as it's diffused co2 in 100%.
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Except for very well tweaked reactors, it will not to be 100% but less. Regardless, people get confused about the DC not getting green with a reactor but green with a diffuser. The reason behind this is quite simple. With a diffuser bubbles can go straight to the DC and the color change will happen faster. Sometimes this can mislead one to think that there is enough CO2 in the tank. With a reactor, CO2 is dissolved in the water and then outgases. This process is more gradual and it takes longer for the solution in the DC to change colors. If however your DC stays blue all day with a reactor this clearly means that you are not injecting a lot of CO2 and you might need to add more.
 
Smykel said:
I was wondering if it could be an good idea to fit inline diffuser before reactor so reactor will have smaller bubbles to break to dissolve in water.
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Interesting question, so instead of having water flow through with Co2 injected through the reactor, you'd basically just have the water flow with much smaller bubbles of co2 already?
I'd be interested in the workings of this too. I absolutely hate the microbubbles in my aquarium, its like watching fish swimming around in a fizzy drink at times. When I contrast that with later in the day when the C02 is switched off, the tank looks so much better. Do these reactors really solve that?
 
Smykel said:
I was wondering if it could be an good idea to fit inline diffuser before reactor so reactor will have smaller bubbles to break to dissolve in water.
Click to expand...
copperband said:
Interesting question, so instead of having water flow through with Co2 injected through the reactor, you'd basically just have the water flow with much smaller bubbles of co2 already?
I'd be interested in the workings of this too. I absolutely hate the microbubbles in my aquarium, its like watching fish swimming around in a fizzy drink at times. When I contrast that with later in the day when the C02 is switched off, the tank looks so much better. Do these reactors really solve that?
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This works but there is a caveat. Your reactor needs to be properly sized in relation to water flow else the small bubbles will go with the flow and end up in the tank. @foxfish had a diffuser in his reactor if I remember well but his reactor was designed and sized in relation to the flow in a way that prevented bubbles from getting carried out by the flow. He can explain better than me.
 
Like @Hanuman said, I think this is the thread.
The problem with microbubbles like those produced by an atomizer are that they are much less buoyant than a slightly larger bubble, and therefore very easily make their way out of the reactor and into the tank.
When you want microbubbles in a tank (like a setup without a reactor), this is one of their greatest features, they dont go up and out the surface so easily.
But the same feature makes them very difficult to keep bobbing around in a reactor.
Then you get microbubbles escaping into the tank anyway, soda look and you are more or less back to square one.

If you use a slightly "worse" atomizer to introduce the bubbles to the reactor, so you dont get microbubbles, but just small-ish bubbles, they should be more buoyant and therefore be a little bit easier to tweak the reactor for. It really comes down to a trade-off between buoyancy and surface area of the bubble. The smaller the bubble, the more surface area it has relative to internal volume. So the smaller it is, the easier it is to dissolve.
 
I see, thanks for the explanation.
One question I have is if around bubbles accumulating in the reactor? I read claims from the manufactures that they dissolve 100% of CO2, but I just can't see how that's possible (unless I'm missing something)? Isn't the principle that the CO2 is injected into a chamber of water containing some sort of plastic media with a flow of water flowing through? What forces all the CO2 to be dissolved?
 
copperband said:
I read claims from the manufactures that they dissolve 100% of CO2, but I just can't see how that's possible (unless I'm missing something)? Isn't the principle that the CO2 is injected into a chamber of water containing some sort of plastic media with a flow of water flowing through? What forces all the CO2 to be dissolved?
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Technically, if no bubbles escape the reactor, then all the CO2 should indeed be dissolved (sooner or later). Even if it forms a large bubble or pocket in the top of the reactor, as long as the pocket is dissolved eventually then it is technically a 100% rate.
Hanuman's point was that it is quite common to have some bubbles escaping a reactor, unless you have taken great care to avoid it (by making sure injection rate, flow and reactor design fit together absolutely perfectly).

The activity of the water surface against the CO2 is what forces it to dissolve. Well designed and adjusted reactors are good at this forcing, and do it quickly. Reactors that are poorly designed or do not fit the system they have been placed in (with regards to flow and injection rate) will be worse at doing this.
If a very large pocket of CO2 is accumulating at the top of your reactor, this can indicate that it either does not fit your injection rate / flow, or that it needs further adjusting.
 
It is a fascinating subject, basically the longer a bubble of C02 is kept in suspension the more effectively it will be dissolved.
For instance if you have a transparent, tall thin tube, lets say 2 m high and 50mm wide that is filled with water and you then inject a single bubble into that tube at the half way point of the vertical tube. The bubble will want to rise to the top, if you now have control over a pump that can force the water downwards against the rising bubble, it will be possible to keep that bubble in suspension until it completely dissolves.
That stye of reactor does indeed work but it needs to be thin and tall because as the bubble gets smaller it will become less buoyant and want to be pushed down the tube.
Most people dont want a two meter tube alongside their tank so other approaches have been developed.

There are many ideas but one obvious method is to spin the bubble around the inside of a tube so the bubble travels a lot further = a vortex reactor.
A properly designed vortex reactor will work very well indeed but they are not easy to DIY and they require lots of adjustment options to tune in the reactor to match the particular circumstances.
Ideally you need mutable valves and flow adjustment so the reactor can be tuned to match the individual requirements.
Unfortunately, most of the commercially available reactors do not offer any adjustment, so you can hardly expect them to work in the same way with one bubble per second, as they would with 10 bubbles per second!

I did spend some time developing a similar design that kept the bubbles in motion, it was simple to DIY by using a commercially available, water, treatment, vessel, and a plastic bottle!
However even that design still requires some tuning to get it exactly on song.
My own reactor has valves and a multi speed pump but it will faultlessly dissolve 10 bps without any bubbles entering the tank.
Here is the link to the reactor with a video…. DIY Project - High flow DIY reactor - now with video
 
Interesting discussion.
Moving back to a slightly more basic discussion, may I ask those with reactors why you added them? Was it more efficient use of CO2 or micro bubbles reduction in the aquarium that prompted the change?
 
copperband said:
Interesting discussion.
Moving back to a slightly more basic discussion, may I ask those with reactors why you added them? Was it more efficient use of CO2 or micro bubbles reduction in the aquarium that prompted the change?
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Both. Efficiency first because it’s always good to be efficient, bubbles second because looking at a soda tank ain’t that great after a while.
 
Hanuman said:
Both. Efficiency first because it’s always good to be efficient, bubbles second because looking at soda tank ain’t that great after a while.
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Are you using a DIY reactor or one you bought? I'd be interested in a recommendation.
 
copperband said:
Are you using a DIY reactor or one you bought? I'd be interested in a recommendation.
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Did it myself. I posted some pictures in some other thread but I’m on my phone now so hard to find. You can make a search in threads I posted related to co2 and reactor. If you can’t find I’ll have a look later when at home.
 
Can't seem to find the post I made. Here it is:
IMG_9922.jpg
 
Well, I'm not getting it. Everyone says (at least on YouTube 😅) that they are using much less co2 with reactors. I had to increase bubbles to about 7-8 and my drop indicator is still blue. Reactor is working as it should. I can see small bubbles going into the outlet. In that speed using co2 I will need to consider to go back to dyfuser. I do understand that big bubbles are going into drop checker so reading can be false.
 
Hi,
The working pressure of the reactor should be much less than with a diffuser, I'm not sure but maybe the amount of gas in the bubble would actually less at lower pressure. I've used 3 x 5kg FEs on my 230l tank in 2 years using the AM1000 and I would say that is quite economical and no bubbles, that is once you've found the sweet spot.
Cheers!
 
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