# Injecting CO2 into Filter



## Kjm (May 27, 2005)

I'm pretty new at planted tanks and would like some advice. I recently set up a 95 long planted tank and I'm wanting to add CO2. 

Someone in a Discus forum recommended that I inject the CO2 directly into the intake line of the Eheim 2028 Professional II filter that I'm going to be using, and bypass using a reactor all together. 

Does this sound logical? If so, any recommendations on how to go about connecting the CO2 line to the filter intake line?

Any advice is greatly appreciated.

Kathy


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## Gonzofish (Mar 26, 2005)

*Co2 injection*

I have had success injecting co2 into a Marineland HOT Magnum filter as a reactor. It works well if you position a ceramic diffuser directly under the intake so that the tiny bubbles are sucked in. I like this because I can shoot a co2 mist onto my plants and they pearl like crazy. Putting the line directly into the canister worries me, and I have not tried it. I would think that co2 would collect at the top of the canister and not make it to the output, resulting in a noisy or worse yet dry filter. Also consider running the co2 line into a powerhead and circulating the water through several feet of tubing and back into the tank. I have had tremendous success with this method, near 100% diffusion with co2 levels of over 30%. I've just recently switched to the canister method because I was tired of disguising the unsightly powerhead. Tom Barr also explains a very good method of diffusion on his website.


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## Kjm (May 27, 2005)

Thanks for the quick reply...I had a feeling that this sounded too easy. Up until recently, I've only had barebottom Discus tanks so substrate, fertilizers, plants, CO2 etc. are all greek to me. So now that you are using a canister, what are you using as a diffuser?

Do you have the link to Tom Barr's website?


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## BrianK (Feb 11, 2006)

I have a setup similar to Gonzo (just set it up today) with the ceramic diffuser below the pump's intake. We'll see how it goes.


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## Gonzofish (Mar 26, 2005)

*Diffuser*

Right now I'm just using a cheap Pollen Beetle ripoff. It's glass with a thin ceramic disc. IMO you don't need a fancy schmancy diffuser if you're injecting into a reactor, just something consistent that won't get clogged and start sending out huge bubbles unexpectedly. A ideal situation for your 95g would be a maximum amount of diffusion with water cycling around the tank so that every plant gets a taste of the saturated water. If the circulation is poor, you'll find plants doing well on one side of the tank and not the other.


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## niko (Jan 28, 2004)

Another way to maximize the efficiency of a diffuser is to place it under the outflow of the filter.

If the filter outflow is L-shaped the fine bubbles coming from the diffuser below can be pushed to the side bu the filter outflow.

If the filter outflow shoots the water straight down the fine bubbles from the diffuser will be pushed down and will linger for a long time in the water struggling to go up.

I personally like the first approach better. Fine bubbles float everywhere and it is best to position the flow along the back wall of the tank otherwise the whole tank looks as if it's boiling. There are no worries about possible airlocking the filter from accumulated CO2 or possible supression of the bacteria activity due to lack of Oxygen.

An alternative to all that is to use a separate powerhead to disperse the bubbles raising from the diffuser. The powerhead can either suck them and discharge them or it can simply push them to the side. The first approach works extremely well with 1/4 inch piece of chinese food chopstick. Just force the chopstick piece in the CO2-tubing and jam it in the powerhead intake. That sounds cheap and simple to work but it takes very little space and the efficiency is amazing. Using that method very, very fine bubbles literally fill my entire 55 gal. tank.

--Nikolay


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