# Want to use eheim canister as co2 diffuser?



## Biznas Man (May 16, 2008)

I have an Eheim 2028 Pro canister on my 38g right now. I have a co2 reactor but would like to be able to just plug my hose from the bubble counter right into the intake of the canister. Anyone know if this canister can be used to diffuse co2 or not?
Thanks
Biz


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## reybie (Jul 18, 2007)

Some do it some don't for fear of choking the filter when an air gap builds up over time. I myself wouldn't do it for that same reason. It might be cheaper just to go with niko's post about that super efficient CO2 reactor for $10 and you get the added water circulation out of it.


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## Biznas Man (May 16, 2008)

I already have a co2 reactor I was just hoping I could plug the air line into the intake of my canister so I could get rid of the powerhead thats running my reactor. I guess the added water flow is nice though. Now I just need to get a surface skimmer attachment to get rid of this film on the top of the water. Thanks.
Biz


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## TWood (Dec 9, 2004)

I use my 2028 as the CO2 reactor, it works fine and has for years.


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## jmontee (Feb 7, 2008)

Biznas, I don't think you need a suface skimmer, I don't know anyone that uses them in planted tanks, I may be wrong though. All I do is move the spraybar from my outlet closer to the surface of the water. It will give some circulation at the top which should help break up the film and some surface disturbance is good for oxygen levels. If this doesn't take care of it you might want to find out why you have so much scum in the water, overfeeding, dying plant material that is not removed, etc. This might be an indication of high TDS (total dissolved solids)/organic compunds in the water. If these build up they can be very harmful to the flora of the tank. How often and how much does the water get changed?


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## houseofcards (Feb 16, 2005)

Biznas Man said:


> I already have a co2 reactor I was just hoping I could plug the air line into the intake of my canister so I could get rid of the powerhead thats running my reactor. I guess the added water flow is nice though. Now I just need to get a surface skimmer attachment to get rid of this film on the top of the water. Thanks.
> Biz


Why do you need the powerhead running the reactor? Just plumb it on the output size of your eheim.


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## Freshwater (Oct 22, 2007)

Hi Biznas, welcome to the forum...

Could you take a few steps back, and tell us what you are trying to do. Tank Specs. and such. Some of us might be able to lead you in a direction that might save you a few bucks. I'm setting up my new Co2 system right now, and choosing to use an inline Co2 reactor on the output side of my canister filter. 

I think it's running me about 16 bucks. Simple and easy, with no chance of "issues" inside the pump head. You can buy them pre-made too.

I will second Jmontee, and House of cards posts. 

Todd


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## Biznas Man (May 16, 2008)

Ok I will start from the beginning.
Tank specs
38g aga tank

Lighting
36" Coralife PC with 2 96w 6700K bulbs alternating throughout the day, six hours on one six on the other etc. I have both of them on for an hour to simulate a high noon effect.

Substrate 
3 inches of Seachems Flourite with about 1/2 inch of pea gravel on top of that

Ferts
I dose what used to be the greg watsons line of dry ferts. Macros one day then micros the next. 
I do weekly water changes of 50% to rid the water of any built up ferts.

Plants
Water wisteria
Blxya Japonica
A few wendti swords
Pygmy valisneria

I never thought of just plumbing in the co2 reactor with the canister. I was just going to run the airline up into the intake and let the impeller diffuse the co2. As far as skum build up goes, it only builds up on the side opposite of the spray of my canister. It isnt a ton, just isn't very nice to look at. I do have the spraybar right below the water line to give some surface aggitation but like I said the other side is calm and so all the build up stays over there. 

Let me know if you would like anymore information.
Thanks for the input.
Biz


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## Left C (Jun 14, 2005)

Biznas Man said:


> ... As far as skum build up goes, it only builds up on the side opposite of the spray of my canister. It isnt a ton, just isn't very nice to look at. I do have the spraybar right below the water line to give some surface aggitation but like I said the other side is calm and so all the build up stays over there. ...


I've read that black mollies will eat the surface scum, but I haven't tried it.

I guess that you could add an AquaClear HOB filter in that area to break the surface of the water in that area if you can't get rid of it any other way.


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## TWood (Dec 9, 2004)

Biznas Man said:


> I never thought of just plumbing in the co2 reactor with the canister. I was just going to run the airline up into the intake and let the impeller diffuse the co2.


Then just do what you already sense is the right thing to do. Putting the reactor on the output side of your 2028 will significantly reduce the flow because they aren't designed to push against very much head.

Take the strainer off the intake tube. Use some wirecutters to break one of the ribs at about the midpoint. Stuff the CO2 line into the resulting opening. Enjoy your tank without a bunch of extra crap attached to it.


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## houseofcards (Feb 16, 2005)

With a 2028 on a 38g, you have plenty of flow to give up in my opinion. If you don't want to worry about your filter and you don't want to see any equipment just plumb it to the output you'll be fine. You could certainly do what TWood said as well, but my vote would be for the output of your eheim.


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## TWood (Dec 9, 2004)

On a 38G the flow reduction may not matter, true. But what I want to dispel is the myth that injecting CO2 into a canister filter is automatically "risky". It's FUD - Fear Uncertainty Doubt. 

On a 2028 it would be impossible to do any damage by injecting CO2 into the intake because the impeller is at the high point of the filter and any gas bubbles present in the water will rise quickly through it, out of the filter, and into the outlet pipe. There's nowhere else for it to go. Unless someone is proposing that an alternate universe exists inside a filter that defies physics as we know it. 

It's your equipment. It's your tank. Take control of it yourself.


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## Left C (Jun 14, 2005)

*Re: Want to use Eheim canister as CO2 diffuser?*

I use an airline elbow for putting CO2 into the intake of a filter. One end has the CO2 tubing connected and the other end is placed into the intake strainer. Then the end that is inserted in the intake strainer is positioned so that the CO2 goes straight up.

http://www.bigalsonline.com/BigAlsUS/ctl3684/cp18283/si1380209/cl0/tomairlineelbow4pk


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## PMM42 (Mar 20, 2008)

I have a Rex style 2"x24" reactor on the output side of my 2217. Works great and I still have good flow. I don't think pumps are as efficient as designed when injecting a gas into the intake. It certainley does cut out a bunch of plumbing and hardware though,


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