Best way to diffuse co2?

[Aquatic Journal]

Hey Guys, 

I am running a fish room with 20 tanks so like many of you I am not running a canister filter. This means for co2 I have a few different options. I can run it off a co2 diffuser, a co2 atomizer, a power head, or an internal filter. There may be other ways as well and I would love to hear what those are.

Has anyone tested this to find out which is the best way to diffuse co2? I have a diffuser running and the drop checker is green but I am not sure if the co2 is moving around enough to get co2 to all my plants as they do not seem to be doing amazing. I just hooked up an internal filter with a co2 line and it seems to have big bubbles but the drop checker is still green and it seems to distribute through the tank better.

Any thoughts are appreciated!

[Koi]

I think using a reactor dissolves the co2 into your water the most efficiently and you don't really get the bubbles flowing around your tank. The claim usually is that reactors dissolve 100% of co2 being used but I think that comes second to having good circulation.

I have never ran side by side experiments on this but I think there is some value to the bubbles floating around the tank. My thought on is this is that you could potentially have more co2 present in the system without needing to fully dissolve it all. So in a sense even at 30ppm of co2 you could technically be offering more co2 as the bubbles are touching the leaves as they flow by. But I don't have any evidence to support this claim, it is just something I've noticed in my experience. I personally just use a in tank glass diffuser with a powerhead/wave maker to spin the bubbles around my tank a few times before they breach the surface.

Something to note, I find that having "30 ppm" of co2 doesn't necessarily mean having good co2. What I mean by this is that when plants begin to fill out a tank, they begin to dampen the water flow and consume more co2 but I think it is more prevalent when trying to push growth in tanks with very high plant mass. In my case, since my tank is relatively taller compared to its other dimensions, increasing water flow and direction has helped in maintaining adequate co2 at substrate level.

[Jungle Fan]

So I've used all of the methods you mentioned, CO2 ceramic diifuser, Aquario Neo diffuser, in tank reactor with pump/power head, inline reactor with bio balls, inline atomizer/diffuser, and in tank atomizer. I've also used one you didn't mention which was the first method to diffuse CO2 over time under water in tank, the glass bell that you manually filled with CO2 from a cylinder via a hose once, or twice a week as it disappeared and was replaced by water. We used to use a cork float  to show how much CO2 had decreased in the bell. I've also seen DIY versions of it made from a variety of plastic bottles.

I didn't like the in tank reactor because it was unsightly and took up space, and if you used the one with the pump added another device to be plugged in, The inline reactor was huge and took up space in the stand under the tank and complicated hose cleaning, the same went in regards to cleaning for the inline atomizer/diffuser because of its ceramic membrane that had to be soaked in bleach every so often to keep it viable and because you now had three sections of hose where you originally only had two. The bell was easy but not very efficient for larger tanks, and I saw much better growth with all other methods.

I also remember hearing Tom Barr, and some other speakers at the Aquatic Gardeners Association over the years talking about the benefits of fine mist CO2 bubbles, over strictly water dissolved CO2. I have never seen their studies in that regard, but their findings seemed to coincide with what I've seen in regards to growth. I don't have an aversion to seeing micro bubbles in my tank, whether it is from CO2, or pearling. If I ran a much larger tank than my current 75 gallon I might consider using a reactor again, or I might just use multiple diffusers.

What I'm currently using is the large Aquario Neo diffuser from Aquarium Co-Op, and the result has made me, and my plants very happy. It produces the finest mist of bubbles I have ever seen a CO2 diffuser produce, and I have a mid sized cardboard box full of different models from ADA, to run of the mill knock offs from an assembly of the finest Asian and European countries to prove it.

When I first received the Neo from Aquarium Co-Op its size had me somewhat concerned that maybe this wasn't a large but I was assured by customer service that it was, and to give it a try as she was using the same for her 100 gallon tank. I'm glad I got it! It works great, and is easy to take care off.

https://www.aquariumcoop.com/collections/plant-supplies/products/aquario-neo-co2-diffuser

Here are two shots of my 75 gallon Amazon inspired tank:

PS: One of the things I remember that was mentioned about the benefits of micro bubbles over strictly water dissolved CO2 also was the fluctuation of CO2 level dissolved in water depending on water temperature, as it decreases with increasing water temperature, just like oxygen which can cause fluctuations.

Edited March 24, 2021 by Jungle Fan
fat finger typo

[DShelton]

1 hour ago, Jungle Fan said:

I also remember hearing Tom Barr, and some other speakers at the Aquatic Gardeners Association over the years talking about the benefits of fine mist CO2 bubbles, over strictly water dissolved CO2. I have never seen their studies in that regard, but their findings seemed to coincide with what I've seen in regards to growth.

I have read this before as well, and not from Tom B. Like you I have not seen a scientific reference that micro-bubbles are more easily absorbed versus dissolved CO2,

 

It does stand to reason they would as most plants grow better emersed versus submerged. That could be attributed to the difference in the CO2 concentration in the air (~400ppm) versus the concentration in water (~30ppm +-).

[Jungle Fan]

@DSheltonORD again otherwise I would have clicked like.