The Aquatic Gazette

CO2 Diffusers

In CO2 on April 20, 2011 at 17:41

CO2 diffusers have come a long way from air stones fitted to DIY CO2 systems . Today, there exist many different methods of diffusing CO2 into our aquariums and each method has its advantages and disadvantages. Here are 5 ways to diffuse CO2 today.

ADA new pollen glass

ADA pollen glass mini

ADA are the inventors of the first CO2 regulator made specially for planted tanks. ADA’s way of diffusing CO2 through a fine ceramic disc is well known and is a staple of the hobby. The workmanship of a pollen glass is quite amazing and the glass is of high quality. One issue with such a diffuser is that algae will accumulate on  the ceramic disc after some time. The removal of algae is a simple overnight bath in a bleach solution, followed by a soak in anti-chlorine solution, to prevent bleach poisoning among the fauna.

Easy Aqua atomizer

Easy Aqua and Green Leaf Aquarium are two companies that are retailing the CO2 atomizer. It is basically the same concept as ADA’s ceramic disc diffuser but with the ability to produce CO2 bubbles that are smaller, leading to better CO2 absorption rate in the water column. A higher working pressure may be needed, compared to a ceramic diffuser as the diffusion holes on the atomizer is smaller.

CAL inline diffuser

Fine CO2 bubbles are all well and good, but if we position a diffuser just below water level, CO2 would have very little time to enter the water column. So, it can be said that a diffuser is more effective if it can extend the time CO2 bubbles are in contact with the water column, as this leads to a higher absorption rate, CAL Aqua Labs’ Inline Diffuser does just that. Instead of being placed inside the aquarium, it is positioned beside a cannister filter and the filter’s outflow tube runs through it, inside the inline diffuser sits a ceramic disc. High-pressured water flow from the cannister filter output, combined with small CO2 bubbles makes for a good CO2 absorption rate. Also, you can position your ourflow pipe in such a way that the CO2 is sprayed into your plants. CAL’s Inline Diffuser is a work of art, well made, and a pleasure to look at during operation.

Up inline atomizer

Relatively new to the diffuser scene is the Up Inline Atomizer. It works in exactly the same way as the CAL’s Inline Diffuser but with the ability of producing smaller CO2 bubbles. Feedback from hobbyists shows that some CO2 systems do not provide enough pressure for this inline atomizer to work effectively, we will be conducting a test soon. Looks wise, CAL’s Inline Diffuser is better looking with its sexy curves and clear glass.

filter impeller

The last method of CO2 diffusion is by attaching a tube, dispensing CO2 gas, into the inflow filter pipe. The CO2 will flow through the filter, gets smashed into smaller bubbles by the filter’s impeller and flow out of the outflow filter pipe. This method gives CO2 the longest contact time as compared to all the other methods above. However, we do not recommend this method because of two problems.

1. CO2 flowing through the filter is not a good thing. Filter bacteria needs oxygen to multiple and break down harmful ammonia, the higher the oxygen count, the better. If positioned properly, the other diffusers do not present the same problem as the CO2 within the water column will be used by the plants, what goes into the filter is oxygen rich water.

2. The dependency of using the filter’s impeller to break CO2 into smaller bubbles can cause the filter to burp on occasion because of a build up as not all CO2 is expelled in equal amounts.  There has also been reports that the concentrated CO2 amount breaks down the impeller’s O ring, leading to a costly replacement.

A poll on AquaScaping World in 2009 revealed the following results out of 96 participants:

Glass Diffusers: 46.74%

Inline Reactor / Diffusers: 39.13%

CO2 direct into filter intake: 7.61%

Others: 6.52%

We expect the Inline Reactor / Diffuser route to be more popular these days as compared to two years ago. Take the poll!







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