# DIY CO2 Reactor Material



## phil4nugen (Aug 24, 2004)

I plan on building a pressure fed CO2 reactor for my 65gal overflow tank.
I would like to place the reactor on the filter (404 Fluval) return line in the overflow to keep it hidden (non-Frankenstein and reduce any leakage concerns). Consequently the water flow will be bottom to top. I plan on using a length of 2" PVC tubing for the chamber and injecting the CO2 into the 3/4" inlet. I see people using gravel, scrubber pads, bio balls, etc. to retain the CO2 bubbles in the reactor chamber.
Any comments on the best material to use and if this system will work.

Thanks,

Mark


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## bharada (Apr 17, 2004)

Mark,
Don't know if there is any 'best' material for creating turbulance in the reactor. I actually use a messily coiled up length of Weed Eater nylon cutting line in both of mine. Creates enough turbulance to dissolve the CO2 without being so bulky as to get clogged.


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## gpodio (Feb 4, 2004)

I think you'd be better off placing it so that the water flow is from top to bottom. I'd also suggest you make the unit in such a way that you can open it to remove or change the materials you use in the chamber. I started with some sponge and quickly realized that with the diameter and flow I used, I was better off with nothing in the reactor at all. The main purpose of the bioballs or other medium in the reactor is to slow down the bubbles and avoid that they pass the reactor completely, instead you want them to float back up to the top of the reactor and get pushed back down by the flow until they are so small they either dissappear or get expelled by the reactor. Having too much restriction often ends up in a big air pocket trapped inside the reactor, not enough restriction and too much flow and the bubbles can't fight the current and simply get expelled.

In the end though, I ended up just feeding the CO2 directly into the canister  works just as good.

Hope that helps
Giancarlo Podio


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## phil4nugen (Aug 24, 2004)

*Intake vs. Output?*

Thanks for the input.
I guess I could inject into to overflow intake tube which flows top to bottom. That tube is about 1 1/2" dia. with an inverted U before the inlet screen. There is an anti-siphon vent on top the elbow that I could insert the CO2 tubing through. I was just worried about gas build up in the Fluval canister if I went that way. Also any media I used would be in the dirty water stream.

I plan to use stainless steel hypodermic tubing at the CO2 inlet to minimize the size of the bubbles to start with. I was hoping that I could get them to dissolve before they reached the top of the 20" tube.
Also because the chamber would be submerged in the overflow I could leave the endcaps a press fit so I can take it apart for easy cleaning.

Mark


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## Rex Grigg (Jan 22, 2004)

I have built several DIY reactors. All from either 1.5" or 2" PVC pipe. I have always plumbed them into the output line of my cannister filter. Always with water flow from top to bottom. I have gotten to the point where at most I will put one Bio-Ball in the reactor. I inject the CO2 at a point about 1/3-1/2 way down the reactor and have never had a problem. I will second the idea of building the reactor so you can take it apart when, note, when not if you need to clean it. The more stuff you put in there the quicker it's going to need cleaning.


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## Vinlo (Jul 27, 2004)

I could not find any bioballs for cheap (plus you only need a small amount), so I used plastic practice golf balls. They look like small whiffle balls. $3 for 12 at walmart. They seem to do the trick.


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