# co2 into canister



## BRUCE BOGMAN (Nov 9, 2006)

i have a xp2 can i feed co2 into the intake,if so will the co2 harm the bacteria.
thx bruce


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## Rex Grigg (Jan 22, 2004)

Why would you think that it would hurt the bacteria? 

I would be more concerned about harming the filter. If you lose power and CO2 builds up in the canister you can burn out the motor or damage the impeller.

Why not build a DIY reactor and plumb it in on the output side of the filter?

I have pictures in my Guide.


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## lenosquid (Oct 9, 2006)

Ok next question: what exactly does a reactor do? Rex that reactor on your website looks just like some PVC that you input CO2 into but doesn't look like it does anything but redirect it. There is a diffuser which creates small bubbles to get them to dissolve into the water column. Why not plumb the reactor into the input of the filter? These might be dumb questions but if there are any simple answers that would be awesome.

since I am getting an Eheim 2126 soon these are important things to figure out..


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## eklikewhoa (Jul 24, 2006)

usually you see bio-balls in the reactor and what it does is the current forces the co2 against the balls and dissolves them into the water.

same thing with pumping it through the canister, the impellar blades hit the co2 and disperse the bubbles everywhere allowing it to easily dissolve into the water column

to use the reactor after the canister is just extra precaution and to keep from wearing the filter.


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## Rex Grigg (Jan 22, 2004)

You never want to restrict the intake on a gravity fed filter.

The way my reactor works is very simple. Water flows in at the top and exits at the bottom. CO2 in injected about 1/3 of the way into this moving column of water. CO2 rises in water. The flow of water keeps the CO2 bubbles rolling around in the column of water till the CO2 is dissolved.

KISS at work. Keep It Simple Stupid.

I don't use nor recommend bio-balls in the reactor. Been there, done that. They will clog up. Then you have to clean the thing. I have one of those reactors running on my 55 gallon tank that has been there for about 3 years now.


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## lenosquid (Oct 9, 2006)

interesting... So you can input the CO2 into the canister via the intake, buuut it will wear out the prop or the motor? Just a higher rate of wear and tear on the filter right? Has anyone had an issue with wear and tear on a canister filter due to the CO2 injection? 

So the reactor is in place of a diffuser...and if done right has a higher efficiency of dissolving the CO2 because the molecules don't hit the surface of the water in the reactor and have more time to dissolve? 

thanks guys


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## redstrat (Apr 3, 2006)

A reactor is much more likely to achieve near 100% dissolution of the CO2 you inject into it than a diffusor. Now that being said, there are MANY people who would argue that a diffusor placed in the tank under the output of the filter creating a CO2 mist will get more CO2 to the plants by means of some of the bubbles actually getting caught under the leaves of the plants and directly touching verses the plant having to extract the dissolved CO2 from the water column. There have been heated debates about this in the past months I'm sure you could find it using the search tool if your interested. 

Personally, I use a reactor on the output side of my XP2 and I love the fact that I dont have tons of bubbles from a diffusor nor the sight of the diffusor in the tank. My plants grow pretty well even with DIY Co2 injected in this manner. I do plan to switch to Pressurized in a couple weeks, but I've been using DIY this way for 6-8months. The reasoning for the Reactor being on the output side of the filter is a matter of pressure, CO2 dissolves much easier under pressure, on the output side of the filter the pump exerts pressure to force the water through the reactor and back into the tank, on the intake side the pressure is much lower because the pump is pulling the water through the pipe and into the filter. Adding resistance to the output side of the filter does not cause harm to the pump, restricting the flow into the filter will. A reactor weather it has bio balls or not will add some resistance to the flow of the water going through it. 

Just my two cents.


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## redstrat (Apr 3, 2006)

Rex Grigg said:


> If you lose power and CO2 builds up in the canister you can burn out the motor or damage the impeller.


I have a small concern about this particular statement, if you hook up your Filstar the way it says in the instructions so there are no dips in the hoses between the filter and the input and outputs in the tank, meaning the hoses are cut to the appropriate length, any gas in the canister will be removed via the water pressure inside and flow out through the pipes back into the tank, this is demonstrated everytime you clean the filter and allow it to refill with water, it uses a gravity fed siphon system to do this.

even if the above was incorrect and you installed the filter incorrectly, and your feeding CO2 through the intake of the filter there is still no threat of gas accumulation in the canister because once the filter stops flowing the co2 bubbles will not be sucked into the filter. If your using a pressurized system with a soleniod valve co2 injection would also stop once the power went off... the only way you could have a problem as quoted would be from directly injecting CO2 into the canister itself, and installing the filter incorrectly so gas could not escape the filter on its own when its off...

all of this being said, if your injecting too much CO2 into the filter inlet it can build up inside the filter while its running, it will escape in bursts through the impeller potentially causing harm the the impeller, but if the power went off... the excess gas would escape if the filter was installed properly.


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## vic46 (Oct 20, 2006)

*Co2*

CO2 won't effect the bacteria in your filter media. However, CO2 is quite hard on plastic and will harm the filter itself over time. Particularly the moving part (the impeller). I have never had the discussion with a manufacturer but I expect any warranty will be null and void if CO2 has been injected into the canister filter. This is also not a very efficient method of CO2 diffusion. In the case of a cannister filter the in-line diffuser in the return line from the cannister is the simplest method. The in-line diffusers are quite simple to build and as they are in the outlet line they will likely never need cleaning. It is also very simple to design the diffuser so that you may take it apart and clean it periodically. If cost is an issue, make 2 and sell one to a buddy for the price of the material. Google - CO2 Diffusers and you will have all sorts of ideas pop up.
Vic


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## diablocanine (Jul 25, 2004)

lenosquid said:


> interesting... So you can input the CO2 into the canister via the intake, buuut it will wear out the prop or the motor? Just a higher rate of wear and tear on the filter right? Has anyone had an issue with wear and tear on a canister filter due to the CO2 injection?
> 
> So the reactor is in place of a diffuser...and if done right has a higher efficiency of dissolving the CO2 because the molecules don't hit the surface of the water in the reactor and have more time to dissolve?
> 
> thanks guys


CO2 injection into a Fluval intake works fine, I did it on several Fluvals for quite some time. I did however, pitch the OEM tubing and intake/return hardware. I got tubing at the local home improvement store and used these for intake/returns. The port for the CO2 is the gray fitting on top of the over the wall assembly.......DC


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## diablocanine (Jul 25, 2004)

Rex Grigg said:


> I would be more concerned about harming the filter. If you lose power and CO2 builds up in the canister you can burn out the motor or damage the impeller.


I didn't have that problem, when/if my filter lost power so did my CO2 solenoid.....DC


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