# My DIY CO2 Reactor Design



## bdement (Jun 4, 2007)

I wanted to submit this to the group to see what you all think about the effectiveness of this reactor design. Unfortunately my test kit is very old, so I couldn't get any hard numbers to contribute to this post. 

I ran 2 DIY Coke bottle canisters into the intake, then wrapped rubber bands around both ends of a sponge prefilter and attached it to the output. CO2 bubbles are broken up by the powerhead's impeller and expelled into the sponge. The powerhead generates a constant flow of water through the sponge and over all the tiny bubbles caught in the sponge. It's got to be working to some extent, because if you squeeze the sponge, a small curtain of bubbles is released!

BTW this is in my 46 Gal Community Tank.


----------



## proudpinoy (Jul 8, 2007)

just watch out for impeller deterioration.


----------



## hoppycalif (Apr 7, 2005)

The reason for introducing the CO2 in the inlet of a powerhead is to generate CO2 mist from the little rotor chopping up the bubbles into tiny ones. But, for what you are doing, why wouldn't it work just as well introducing the CO2 in the outlet, so it ends up in the filter sponge? That keeps the bubbles from affecting the rotor. However, I ran a Maxijet 600 with the CO2 going into the inlet for several months with no damage to the rotor that I could see.


----------



## bdement (Jun 4, 2007)

hoppycalif said:


> The reason for introducing the CO2 in the inlet of a powerhead is to generate CO2 mist from the little rotor chopping up the bubbles into tiny ones. But, for what you are doing, why wouldn't it work just as well introducing the CO2 in the outlet, so it ends up in the filter sponge? That keeps the bubbles from affecting the rotor. However, I ran a Maxijet 600 with the CO2 going into the inlet for several months with no damage to the rotor that I could see.


Good point, in my case it'd make wrangling the airlines more difficult, but it probably would work just the same inside the sponge. It'd be worth a test, ....if I had a test kit, doh


----------



## bdement (Jun 4, 2007)

proudpinoy said:


> just watch out for impeller deterioration.


I can totally see impeller problems down the road. I've had to replace the CO2 lines because the CO2 hardened them. Does CO2 affect plastics or what?


----------



## vicpinto (Mar 27, 2007)

I'd put it on the output myself. There are plenty of threads here discussing the pro and cons of intake v output.


----------



## hoppycalif (Apr 7, 2005)

CO2 does tend to harden plastic airline tubing. I think vinyl is the worst that way, but I notice hardening with silicone and the "CO2 proof" clippard tubing too.


----------



## Squawkbert (Jan 3, 2007)

Since you have an Eheim, you could just feed the CO2 into the pictured green inlet basket.


----------



## bdement (Jun 4, 2007)

Squawkbert said:


> Since you have an Eheim, you could just feed the CO2 into the pictured green inlet basket.


Agreed. I've been reading some other threads and that method does have the reputation as being even more effective. That would also give me a couple more square inches of planting space  not to mention one less piece of equipment to power and maintain. I'll try it out ASAP!

Many people are also saying that CO2 should go into the output of the Eheim, but I haven't found any descriptions of how to plumb that yet!


----------



## Squawkbert (Jan 3, 2007)

That would not make a lot of sense. Eheims are tough, don't cavitate and do a nice job of chopping bubbles up.

If you want to feed just one piece of tubing into the Eheim, you could T-the lines together, then just run the one into the tank.


----------



## bdement (Jun 4, 2007)

Squawkbert said:


> That would not make a lot of sense. Eheims are tough, don't cavitate and do a nice job of chopping bubbles up.
> 
> If you want to feed just one piece of tubing into the Eheim, you could T-the lines together, then just run the one into the tank.


You are the man, sir! Will do!


----------



## plantkeeper (Apr 30, 2007)

You can use an airstone below the imput of the powerhead to help minimize cavitation. This will be maintain the impellers for longer period of time. Use the powerhead to increase water contact time by pushing it down and out more than "churning the bubbles". 

JMO and my $0.02.


----------

