Most efficient diffuser

[andy]

As per title really....the ceramic diffusers seem to waste a lot of CO2

I used the tetra ladder years ago and that seems good...you could see the CO2 bubbles getting smaller due to the long contact time with the water.

Any other suggestions? I don't have room for a reactor

Just looked at the JBL Proflora spiral which seems to allow a lot of contact time with the water. Anyone used it ?

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[Connswater]

JBL Proflora spiral which seems to allow a lot of contact time with the water. Anyone used it ?

Yes, works well.

An in-line ceramic works better, at least for a year or so. A good reactor - if in tank, with driven paddles - even more so, however, there is maintenance involved, after a while mulm etc., settles inside it seems to impede the paddles and also a filter must be strong enough but not too strong, and filters need maintenance, but I read what you wrote and you can't really use a reactor and I have found external reactors (cheaper versions) incredibly difficult to get to work properly.

I am using a buzuka currently, but blasted by an internal filter, otherwise it would be too inefficient.

 

[Nuno da Silva]

As per title really....the ceramic diffusers seem to waste a lot of CO2

Hello Andy,

Why do you say that? I always thought they were very good at producing microbubbles and great gas exchange surface

 

[Marcel G]

From my point of view, Yugang's CO2 Spray bar is clearly the most effective and, moreover, undoubtedly the safest solution. I made a smaller version of it for my experimental aquariums: co2-diffuser-for-nano-tanks. The principle of how it works is that you put a container of some sort in the aquarium, bottom up (Yugang uses a clear plastic tube, I used a glass lab beaker), pump CO2 into it from a pressurized bottle, and the flow of water makes sure that the CO2 spontaneously diffuses into the water. The advantages of this solution are that (1) the CO2 concentration in the aquarium will be unbeatably stable (the exact value depends only on the size of the surface area of the container and the water level in the aquarium), (2) dosing CO2 becomes so simple that even a complete beginner can do it, and no expensive needle valve is needed (the only thing one has to ensure is that the container is always full; you might as well add a little more CO2, because any excess will escape from the container to the surface and out of the aquarium).

Here's a video:

 

[LMuhlen]

Hello Andy,

Why do you say that? I always thought they were very good at producing microbubbles and great gas exchange surface

While it is effective, in most cases there are a lot of bubbles that end up reaching the surface and dispersing the gas to the atmosphere. Even if most of the gas has been absorbed by the water before the bubble reaches the surface, still some part of it is lost. Unlike reactors, that aim at dissolving all the gas and not losing anything.

I have my own personal theory that when we form those micro-bubbles that get dragged by the currents and never seem to disappear completely, that those bubbles are not CO2 anymore and must be gases that were dissolved in water and that escaped to the bubbles, against the main flow of CO2. I say this because it is easy to observe how the larger initial bubbles reduce in size (and therefore upwards velocity) quite fast in water, but then when they should be disapearing, it seems like they stop shrinking and last forever. If this were the case, then it is possible that the perceived losses of CO2 to the atmosphere is smaller than what we might think.

I do have a counter personal theory as well 🤷‍♂️ It is that micro turbulence on the immediate surroundings of the bubble are very important for the gas dissolution rate. When the bubble is large, it goes against the flow of water, straight up, and the resistance it encounters on its way generates this surrounding turbulence. We can observe it somewhat by looking at how slightly larger bubbles zigzag upwards instead of going straight up. But when the bubble is so small that it gets carried by the water currents, there is no friction, no resistance, and therefore no turbulence generated. While the surface/volume ratio is great and this very last bit of gas remaining in that tiny drop should be absorbed in no time, the lack of turbulence drops the dissolution rate drastically. If this is the case, the ideal bubble size is that which is small enough to not go too fast upwards, that zigzags a bit, but not so small that it just goes with the flow offering no resistance.

Of course, both theories could work at the same time. And of course, they may both be wrong. The fact is that it seems very weird that those nano bubbles seem to last too much and cloud the tank, while concentrated CO2 should be very easy to dissolve in water.

 

[Nuno da Silva]

I have my own personal theory that when we form those micro-bubbles that get dragged by the currents and never seem to disappear completely, that those bubbles are not CO2 anymore and must be gases that were dissolved in water and that escaped to the bubbles, against the main flow of CO2. I say this because it is easy to observe how the larger initial bubbles reduce in size (and therefore upwards velocity) quite fast in water, but then when they should be disapearing, it seems like they stop shrinking and last forever. If this were the case, then it is possible that the perceived losses of CO2 to the atmosphere is smaller than what we might think.

This is what I always thought was the general understanding of what is happening in the bubble. Co2 goes out but some gases, like oxygen goes in the bubble. By the time it reaches the surface the amount of co2 loss is minimal.

I do have a counter personal theory as well 🤷‍♂️ It is that micro turbulence on the immediate surroundings of the bubble are very important for the gas dissolution rate. When the bubble is large, it goes against the flow of water, straight up, and the resistance it encounters on its way generates this surrounding turbulence. We can observe it somewhat by looking at how slightly larger bubbles zigzag upwards instead of going straight up. But when the bubble is so small that it gets carried by the water currents, there is no friction, no resistance, and therefore no turbulence generated. While the surface/volume ratio is great and this very last bit of gas remaining in that tiny drop should be absorbed in no time, the lack of turbulence drops the dissolution rate drastically. If this is the case, the ideal bubble size is that which is small enough to not go too fast upwards, that zigzags a bit, but not so small that it just goes with the flow offering no resistance.

It's certainly very interesting point of view, makes sense and would explain why in a reactor you get 100% dissolution of the bubble. I wonder if someone has some scientific insight into this!

 

[Nuno da Silva]

From my point of view, Yugang's CO2 Spray bar is clearly the most effective and, moreover, undoubtedly the safest solution. I made a smaller version of it for my experimental aquariums: co2-diffuser-for-nano-tanks. The principle of how it works is that you put a container of some sort in the aquarium, bottom up (Yugang uses a clear plastic tube, I used a glass lab beaker), pump CO2 into it from a pressurized bottle, and the flow of water makes sure that the CO2 spontaneously diffuses into the water. The advantages of this solution are that (1) the CO2 concentration in the aquarium will be unbeatably stable (the exact value depends only on the size of the surface area of the container and the water level in the aquarium), (2) dosing CO2 becomes so simple that even a complete beginner can do it, and no expensive needle valve is needed (the only thing one has to ensure is that the container is always full; you might as well add a little more CO2, because any excess will escape from the container to the surface and out of the aquarium).

Here's a video:

Hi Marcel,

We are talking about improving the efficiency of a ceramic diffuser (that produces microbubbles) but I failed to understand how your suggested method is improving the efficiency if you are pushing more gas into the container than what it can actually dissolve (with the excess going straight to the atmosphere).

 

[Marcel G]

We are talking about improving the efficiency of a ceramic diffuser (that produces microbubbles) but I failed to understand how your suggested method is improving the efficiency if you are pushing more gas into the container than what it can actually dissolve (with the excess going straight to the atmosphere).

The title of the thread is "Most efficient diffuser" (not "most efficient ceramic diffuser"), from which I inferred that you were looking for [whatever] the most efficient method of dissolving CO2. In your first post you then criticize "ceramic diffusers" as inefficient. Therefore, I was trying to show you an alternative method that is definitely more efficient, and furthermore, unparalleled safe and accurate (!) as far as the amount of CO2 you will have in your aquarium. The amount of CO2 in the aquarium does not change or fluctuate with this method - regardless of whether you add a little or a lot of CO2 to the aquarium (as long as you ensure that the CO2 container is always full to the brim). The important thing is just to choose the right size of the container (this determines the amount of CO2 that dissolves into the water). The overflow is just for safety (and practical) reasons. In my aquariums, one bubble escapes through this overflow every 5 minutes or so, which [in my opinion] is a totally negligible amount. The CO2 dissolution efficiency is therefore [unlike ceramic diffusers] practically 100%. But there is also a reactor version.

 

[Nuno da Silva]

The title of the thread is "Most efficient diffuser" (not "most efficient ceramic diffuser"), from which I inferred that you were looking for [whatever] the most efficient method of dissolving CO2.

Correct!

In your first post you then criticize "ceramic diffusers" as inefficient.

I was actually arguing in defense of the ceramic diffusers! The bubbles that reach the surface are probably not 100% CO2 anymore!

Therefore, I was trying to show you an alternative method that is definitely more efficient, and furthermore, unparalleled safe and accurate (!) as far as the amount of CO2 you will have in your aquarium. The amount of CO2 in the aquarium does not change or fluctuate with this method - regardless of whether you add a little or a lot of CO2 to the aquarium (as long as you ensure that the CO2 container is always full to the brim). The important thing is just to choose the right size of the container (this determines the amount of CO2 that dissolves into the water). The overflow is just for safety (and practical) reasons. In my aquariums, one bubble escapes through this overflow every 5 minutes or so, which [in my opinion] is a totally negligible amount. The CO2 dissolution efficiency is therefore [unlike ceramic diffusers] practically 100%. But there is also a reactor version.

Do you have any idea of how many bubbles per second you are introducing in your container? Do you have any idea of the quantity of CO2 you have dissolved in the aquarium water?

I'm struggling with your system because having an up side down container with CO2 like yours generate a very small surface area for gas exchange. And you can't direct flow into it, otherwise you will disturb the giant bubble.

Cheers

 

[Marcel G]

Your questions indicate that you probably don't understand the principle behind the Yugang's diffuser. I don't mean this as a criticism by any means, but I would suggest you review the links I provided in my posts. Everything is explained there. Again, I would like to reiterate that my goal is not to convince anyone, but to provide information. What you do with it is up to you.