# How to inject CO2 into Rena XP1?



## u2_crazy (Dec 19, 2006)

Is there a way to pipe the DIY CO2 into the output of the XP1? I use standard silicon tubing.


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## ed seeley (Dec 1, 2006)

Just cut a small hole in the filter tubing, slice the CO2 line to form a point and shove it through. Then, to be safe, silicone seal all around it to form a watertight seal.

Like this!









And this!









The only problem is you won't get very good diffusion of the CO2, the bubbles produced will mainly just go straight up out of the outlet into the air above the tank. Some people do inject CO2 into the inlet, but i was worried that would cause noise issues in the filter and possibly damage it, but people do seemingly without harm.

If you're wondering why i then have photos of what i am saying won't work(!) the first photo shows a jury rigged venturi that sucked the excess CO2 from the top of my JBL Diffusor









I then decided the whole JBL diffusor wasn't good enough so made my own CO2 reactor from a gravel cleaner and the second photo is how the CO2 is injected into the flow just above the reactor. It's been working well for two days now, i've got great pearling on the plants and only the occasional, microscopic, gas bubble comes into the tank.


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## adamt (Oct 21, 2006)

Or you could buy one of these


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## Left Coast DJ (Nov 16, 2006)

Anyone try connecting the CO2 line straight into the venturi plug of outflow regulator?

DJ


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## adamt (Oct 21, 2006)

This probably isn't exactly what you are talking about, but it might help if that is what you want to do.

http://www.aquaticplantcentral.com/forumapc/do-it-yourself/31026-barr-internal-venturi-co2-reactor.html?highlight=Venturi+Reactor


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## ed seeley (Dec 1, 2006)

adamt said:


> Or you could buy one of these


That looks like it would be perfect for my CO2 reactor. Where do you get them from and do you know if they are available over in the UK/Europe?


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## adamt (Oct 21, 2006)

You might want to check your local hardware/building supply store. I'm unfamilar with what is available in Europe and the UK. I didn't realize you were from the UK. The picture I originally posted is from the website marinedepot.com. I'm not sure if they sell to Europe or the UK. You might check that out too.

Either way, the hose barb fitting you want to get is a Reducing Tee 16mmX4mm.

Sorry I couldn't help out more

Adam


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## jon_the_newb (Dec 30, 2006)

Left Coast DJ said:


> Anyone try connecting the CO2 line straight into the venturi plug of outflow regulator?


The plug is so close to the return, I think the CO2 will just get shot out into the tank and not dissolved into the water very well.

Jon


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## Left Coast DJ (Nov 16, 2006)

jon_the_newb said:


> The plug is so close to the return, I think the CO2 will just get shot out into the tank and not dissolved into the water very well.
> 
> Jon


What if you fix the flow control further up the return line? Wouldn't it work somewhat like a ready-made inline reactor? I have this plug connected to an air pump. But I've never tried it with CO2.

DJ


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## jon_the_newb (Dec 30, 2006)

To get it really dissolved into the water you want it to linger more. Check out Rex's Guide to Planted Tanks . He has some good info on CO2 injection and building a DIY CO2 reactor.

Jon


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## danepatrick (Sep 18, 2006)

don't inject all of that co2 into your filter. too much air is going to make your impellar too hot and burn it up very fast. it's not good for your filter.


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## Left Coast DJ (Nov 16, 2006)

DP, the air is pumped into the venturi plug on the return side, not the intake side. So no air goes through the impeller.


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