# CO2 equipment (reactors diffusers)



## TropTrea (Jan 10, 2014)

I'm in the process of converting a 120 gallon tank to a planted South American tank. Do to the size of the tank I want to get everything as efficient as possible including the CO2 system. My major concern in the efficient injection of CO2 into the aquarium water. I know the standard methods are diffuses or reactors. However I'm at loss as to what is on the market today as far as efficient CO2 reactors. So I'm looking for multiple suggestions here. 

Note I used CO'2 on many tanks going 12 or more years back but moved to reefs in last 15 years. Now I'm looking at going back at least part way to the planted fresh water tanks. I really miss my plants and my discus. But I'm sure the technology advanced since then so please everyone give me a crash course in reactors.


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## Tugg (Jul 28, 2013)

Does anyone actually buy one? I built a Rexx Grigg design. There are a few modified versions that include a venturi pump to recycle any build up of CO2.

Googleing "DIY CO2 reactor" should get you a pile of How-Tos to build from. The simplist is the Rexx Grigg. It basically just a lengh of PVC with an CO2 Airline ran to the top. The basic theory is that water comes in the top, and leaves the bottom. Since CO2 will try to rise, it counter flows with the falling water and is quickly absorbed as it fights to rise in the pipe.


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## BruceF (Aug 5, 2011)

I wonder if the Ista reactor isn't good? It sure is cheap.


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## TropTrea (Jan 10, 2014)

BruceF said:


> I wonder if the Ista reactor isn't good? It sure is cheap.


I looked at the Ista page to see what you were talking about.The design seems simple however I'm not sure it work for me. "Uses the flow from your filter" Well I'm planning on using a 250 gph filter for the 120 gallon tank so I would think the flow would way to high for this reactor. But just looking at the web picture I could be completely wrong.

I looked at some DIY plans and looks like they vary considerably but everyone is still using the same principles they used roughly 15 years ago. My thoughts now are possibly build one based an a very small power head. The power head would be used to circulate water downward through a chamber where it would mixed with the CO2 gas. It would be close to the design of some of the earlier protein skimmers with the exception the the top would sealed.

Yes this has some wild ideas running through my head, Did you see the RED SEA reactor for $150. it looks almost like it could turn your tank into CO2 water. I want efficiency but not at that kind of price compared to the cost of CO2.


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## BruceF (Aug 5, 2011)

Lots of people use needle wheel impellers. It is all about the bubbles and not ending up with 7 up as they say.


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## TropTrea (Jan 10, 2014)

BruceF said:


> Lots of people use needle wheel impellers. It is all about the bubbles and not ending up with 7 up as they say.


Yes that is the same principle with protein skimmers. The big difference is were looking at a much smaller ratio of gas. Inject the CO2 bubbled water near the bottom of the container then have in come out at a point lower than it was injected with the help of a tube that reaches near the sealed top.

Now to visit the plastics place to see what they have in acrylic tubes for the construction.

Gee when I decided to move away from reefs I though I was going to end my acrylic projects.


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## TropTrea (Jan 10, 2014)

Hopefully here is a picture of what I'm thinking of building. Dimensions are up in the air as I have to see what is available in acrylic or poly carbonate tubing sizes and my plastics dealer. But I'm planning on using clear rigid tubing. The needle wheel power head would be also helpful but I don't want to go to large on this punk either. This will all be in the tank and the tubing on the bottom of the picture is designed to allow the CO2 enriched water to enter the tank at two specific points near the bottom. 

Opinions would be greatly appreciated. Do you think it will work? How can it be improved for efficiency?


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## TAB (Feb 7, 2009)

search my threads, i built some a few years back for several people, for basicly what i had in them + shiping. 2" is a good size with the thicker wall. IME counter current is not need if you keep the flow rate less then 400 and you have ~ 18" of tube. CC really increase your head dramticly do to the bends in the pipe.


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## niko (Jan 28, 2004)

No matter how you twist it the cheapest and extremely efficient method is to stick the end of the CO2 tubing in the intake of a powerhead. Cover the outtake with a sponge. The bubbles get trapped in the sponge and the water rushes by them. Tiny bubbles make it out but they are so small that look like dust that very slowly raises to the surface.

Easy to maintain. And the quiet sound that each bubble makes when it hits the impeller serves as a bubble counter.

Only downside - the pump need to be inside the tank.


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## TAB (Feb 7, 2009)

still not quiet enough for my tastes. my system is silent now. the only noise i have is when my ato kicks in. thats only becuase it is air powered( 5 gal water jug used to hold a small ammount of air pressure to force water thru a dip tupe) its the only thing i have not found to really get quiet and still work with a decent safety factor.


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## jocky (Jun 24, 2008)

I stick the co2 tube into the intake of my canister filter and just let it chop up the bubbles. By the time the water gets back to the tank there's no bubbles. I'd take that with a larger tank get a big enough filter for it and that would be sufficient. A powerhead next to the return to distribute the co2 into the depth of the tank would be even more efficient.


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## TropTrea (Jan 10, 2014)

jocky said:


> I stick the co2 tube into the intake of my canister filter and just let it chop up the bubbles. By the time the water gets back to the tank there's no bubbles. I'd take that with a larger tank get a big enough filter for it and that would be sufficient. A powerhead next to the return to distribute the co2 into the depth of the tank would be even more efficient.


Considering I'm planning on using Magnum 250 HOT filters this might not be a bad idea. I used to use the Magnum 350 Canisters but they are no longer made from what I can tell.


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