# Best CO2 diffuser/reactor for big tank? Advice please!



## Kip (Jun 27, 2007)

Hi I've got a 250 gallon iwagumi, and I've been trying to coax my Red Sea 500 reactor with pressurized CO2 but it's just barely making the grade.

Can anyone recommend a better way of dissolving my pressurized CO2? Perhaps something like the Aqua Medic 1000 or something like that?

I'd like to use something that is minimal and attractive... either something I could put in my overflow box or something beautiful like the ADA diffusers.

Any advice is welcomed. Thanks.


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## Rex Grigg (Dec 10, 2002)

Best advice I can give you is build a DIY PVC reactor and plumb it in on your return line.

That's a large tank and needs a big reactor. I highly doubt any commercial reactor is up to the tanks. And diffusers on a tank that size would require several diffusers along with a manifold and several needle valves on the CO2 system.


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## ringram (Jan 19, 2005)

For a tank that size, you may want to get a manifold to split the Co2 line into two outputs. You then have several options. You can get two diffusers and put them at either end of the tank. If flow rate in the tank is sufficient, it should be fine. You could also try a PVC reactor in your return line AND a diffuser. It's your choice, but I'm not sure that just one Co2 injection point on such a large tank will be enough.


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## tazcrash69 (Sep 27, 2005)

I used to have problems gettting my CO2 where I wanted it in my 125. I got a manifold from http://www.bestaquariumregulator.com/, and 2 needle valves. Did my own bubble counters going to 2 Aqua Medic 1000's . But those reacots just weren't doing the job running off of 2026's so I made 2 DIY ones, and can finally get the rate I want with no huge gas bubble. 
There should be a couple manifold pics in my gallery in the sig. 

If you are running a sump, and the output is split, this is the way I would go.


HTH
Good luck.


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## tropicalfish (Mar 29, 2007)

Why are two needle valves necessary when diffusing into the same tank?

I was thinking something simpler like this:

Regulator --> Solenoid --> Needle Valve --> Check Valve --> Bubble Counter --> Check Valve --> T-valve --> diffusers

rather than:

Regulator --> Solenoid --> Manifold --> 
->Needle Valve --> Check Valve --> Bubble Counter --> Check Valve --> diffuser
->Needle Valve --> Check Valve --> Bubble Counter --> Check Valve --> diffuser


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## David Hui (Sep 14, 2005)

Did you say overflow? What type of filter do you use? And, if you use a sump how did you minimize CO2 lost.


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## Kip (Jun 27, 2007)

I have a big eheim running below tank (I think it's the 2028?) ... since it is a wet intake and wet output (no surface breaks) it doesn't seem to leech CO2 much.

I also have a second powerhead helping circulate water. Right now I'm suing the Red Sea 500 reactor, which is only rated for 125 gallons. At a high rate of CO2 (~8 bubbles/sec) it can't mix it all, but the overflow CO2 gets hit by the second powerhead in tank and mixes around a bit. 

With this setup, I can just about get my drop checker to read green. What I'd like to do is set this all up in the overflow area of the tank (where the input to the eheim is) ... hopefully the AM 1000 can do it since it's rated for 500 gallons. 

From the posts here, it seems many of you are skeptical of that claim though, yes?


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## Rex Grigg (Dec 10, 2002)

If you simply split a CO2 line after a control valve then the CO2 will take the path of least resistance. So one diffuser will get most of the gas. 

It's a simple fact of physics.


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## tropicalfish (Mar 29, 2007)

What if I use the same length of tubing and same diffusers?


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## epicfish (Sep 11, 2006)

tropicalfish said:


> What if I use the same length of tubing and same diffusers?


Different diffusers have different ceramic discs which aren't all made the same. You'll be better off getting a manifold and two needle valves.

To the OP, I'd split your CO2 outflow into two with a manifold and two needle valves. At least one line would go to a venturi-type Mazzei injector...and the other probably to a DIY CO2 reactor.


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## David Hui (Sep 14, 2005)

One thing I know for sure AM1000 won't it for you because it use's 1/2 inch tubing and it will slow the flow. I would go with two DIY external reactor along with one CO2 diffusor on a three ways manifold.


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## Rex Grigg (Dec 10, 2002)

tropicalfish said:


> What if I use the same length of tubing and same diffusers?


Nice try. But 99% of the time it won't work. The pressure in the line after the needle valve is so low that just a tiny difference in the back pressure of the diffuser will cause the least resistance problem.


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## oblongshrimp (Jul 26, 2006)

On a 120 gal tank I use 2 5k Rhinox with a Rio powerhead sitting ontop of each to blow the bubbles around. I can easily get my CO2 high enough and can gas my fish if I turn it to high so something similar may work for you. I also have the manifold and use 2 needle valves.


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## scolley (Apr 4, 2004)

Skip the diffuser, skip the reactor. On a tank that size IMO you should go straight for the Mazzei venturi. It's all you will need.

Use the search function to see how to hook one up, but bottom line - if you buy the right sized venturi, you'll have NO PROBLEM getting all the CO2 you could possibly want into your tank.


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## Justintoxicated (Oct 18, 2006)

you could get like 6 Red Sea 500's lol


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## ringram (Jan 19, 2005)

it's not just the length of the hose that will add to resistance. It also involves how easy it is for the Co2 to bubble through the ceramic disk or bioballs (in a reactor). I've heard from many people that separate needle valves are recommended if you're splitting a line with a manifold. I've never tried splitting a Co2 line, so I can't really comment on experiences, just what I've heard from numerous people.



tropicalfish said:


> What if I use the same length of tubing and same diffusers?


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## Geobelle (Feb 28, 2004)

I would get an Elos reactor 50 for that matter, CO2 dissolve 100% in water. Little bit expensive coz it's purely specal handmade glass made in Italy but it works perfectly amongst other glass diffuser.


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