# Survey for External CO2 Reactor Users



## ksand (Oct 19, 2004)

I would appreciate very much if some external-reactor users would respond to this survey. I've done quite a bit of leg-work myself already: I've searched this forum, experimented with PVC and different pumps, etc, but I have a few questions:

When a well-configured reactor is working the way it should, is the chamber completely filled with water? What should the back-pressure be on the CO2 line going in.. a lot, a little, negative? What about the noise factor, both from the pump and from the reactor itself?

I would really like to hear people's comments and advice on how to do it right.


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## Ibn (Nov 19, 2003)

The reactor should definitely be completely filled w/water when it's running.

Not sure about the back pressure on the line, since I've always run a check valve of some sort or another. Just makes sense to spend $10 or so instead of having to replace a regulator.

The reactor is on the output side of my Eheim 2128. The Eheim is virtually silent and so is the reactor. If I crank the bubble rate up, then you can hear the bubble counter going.


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## ksand (Oct 19, 2004)

You've pretty much got the exact same setup I've been picturing in my mind. That's 2", right? Thanks for the info, at least now I know that the "perfect setup" is possible, and you've achieved it 

Where does the CO2 go in? Are you using 1/8" tubing for the gas line?

Oops sorry I just noticed the fitting. So you inject the gas near the bottom and the water flow is from top to bottom? Could you tell me how you get the gas line into the reactor, and how confidant you are of the seal?


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## Ibn (Nov 19, 2003)

Yup, that's 2" polycarbonate there. No such thing as a perfect setup, but just whatever works. In retrospect, I would go w/a larger diameter tube (3") and shove more bioballs into it (that one only has 9 in there). This would really allow you to crank the CO2 levels up, even in a larger tank, but as is, it works well. 

Glad you caught the airstone connector there on the bottom. It's basically an airline connector (they come either as a single or in a multi-pack) that's glued onto the polycarbonate (drill a hole in the tube first) using plumber's goop. The seal is good. That's the second reactor that I've built and there have been no leaks in either of them. Here's the first reactor that I built:









It uses the standard airline tubing (same as CO2 tubing). Other than that, you have the other details down.


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## Laith (Jul 7, 2004)

Nice to have the wine close at hand when contemplating the tank! roud:


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## jart (Jan 17, 2003)

ksand said:


> What should the back-pressure be on the CO2 line going in.. a lot, a little, negative? What about the noise factor, both from the pump and from the reactor itself?


the back pressure on my reactor (similar to ibn's) is huge. i would recommend a check valve highly for this reason. i can't comment on the noise because i've never had my cannister set up without the reactor inline.


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## ksand (Oct 19, 2004)

Ibn, what kind of glue did you use? I like the look of the check valves sold by Glass Gardens. What's that Hagen canister doing there ?

Jart, so with that kind of back-pressure, then one could never use a yeast generator with an external reactor, right? I guess with a CO2 regulator, you set the output to 10-20psi and that's enough to overcome the back pressure and force the gas into the water stream.

I have a powerhead that has a "venturi port", and you basically attach a piece of airline tubing at the outlet nozzle, and it sucks air _in_ to the water stream. ...... Heh heh, forgive me, indulge me, I'm just fascinated by this stuff.


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## Ibn (Nov 19, 2003)

To piece the reactor together, I just used regular PVC glue. As for the airline connector, I used plumber's goop (got it from OSH) to attach it to the side of the tubing.


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## jart (Jan 17, 2003)

i used glue as shown here: http://aquabotanicwetthumb.infopop.cc/eve/ubb.x?q=Y&a=tpc&s=4006090712&f=8006023812&m=1276009343&p=1

there are 2 cans; a primer and the glue itself.

i have never used diy co2 so i can't comment on whether you could use such a reactor with it. i have my regulator set at 20, yes, but you also need a needle valve of course to fine tune the gas. i have my check valve between the needle valve and the bubble counter.


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## ksand (Oct 19, 2004)

That's a great link, Jart, I never ran across that one and I've done lots of web searches on the subject. Thanks much, folks. roud:


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## jart (Jan 17, 2003)

other good step by step instructions include Ghazanfar Ghori's http://aquabotanicwetthumb.infopop.cc/eve/ubb.x?q=Y&a=tpc&s=4006090712&f=8006023812&m=9556098022&p=1

and wellbiz's on this site.


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## rkundla (Mar 25, 2004)

ksand said:


> Jart, so with that kind of back-pressure, then one could never use a yeast generator with an external reactor, right? I guess with a CO2 regulator, you set the output to 10-20psi and that's enough to overcome the back pressure and force the gas into the water stream.


If your reactor is on the output of your canister filter, the pump is pushing water through the reactor and the airline connector is another exit from the reactor. DIY CO2 may not generate enough forward gas pressure to compensate for the liquid pressure leaving the reactor. Pressurized CO2 blows through that water pressure nicely. :icon_bigg 



ksand said:


> I have a powerhead that has a "venturi port", and you basically attach a piece of airline tubing at the outlet nozzle, and it sucks air _in_ to the water stream. ...... Heh heh, forgive me, indulge me, I'm just fascinated by this stuff.


This can be dangerous in the opposite direction. Venturis create negative pressure (vacuum) while can be dangerous for DIY CO2. The vacuum in the line can collapse your DIY container if it gets to high. Some people have recommended using thick glass containers because they can handle the higher negative pressure.

With DIY, most people stick with the low backpressure methods like ladders, bells and such. The last thing you want is smelly yeast mixture blown all over your walls or the inside of your tank stand.


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## glass-gardens.com (Apr 14, 2004)

I ran DIY CO2 into an AM500 reactor, which actually creates back pressure on the CO2 line as opposed to a vacuum.

The inline reactors as well seem to have back pressure as opposed to a venturi effect, all one needs to do to verify this is to disconnect the CO2 line and raise it above the level of the tank and watch the water run out instead of getting sucked back into the tube until it sucks air.


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## GulfCoastAquarian (Jul 30, 2002)

I'm using an external reactor similar to Ghanzafar's (without bioballs). The chamber isn't always completely filled with water, though. I do hear some splashing. I need to get my hands on a few bioballs to create some turbulence to help the gases dissolve quicker.
I recently moved the reactor from the outlet of a Fluval 403 canister to just a 600lph powerhead. The water coming out of the Fluval was under significant pressure, which helped the CO2 diffuse more easily and the bioballs weren't necessary. Now that the flowrate and pressure is much lower, I believe some turbulence is needed to increase efficiency.


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## ksand (Oct 19, 2004)

GulfCoastAquarian said:


> ...I recently moved the reactor from the outlet of a Fluval 403 canister to just a 600lph powerhead...


600 lph is about 160 gph. Ibn's 2128 pushes about 260 g.p.h. I've been playing around with this reactor from Aquatic Store:










...and 172 gph is NOT enough... the water kind of trickles through it. But a Rio 1400 (400 gph) fills it up nicely... but too strong a flow for a small tank. 

So a flow rate between 260 and 400 gph should be ideal. Thank you all for the replies.


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## GulfCoastAquarian (Jul 30, 2002)

Yeah, we need to make it clear that a Rio600 is not adequate for an external reactor! I might pick up a 1400 next time I place an order with Big Al's.


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## ksand (Oct 19, 2004)

Actually, I feel that the 1400 might be overkill. I don't like the strong current, but that's a personal preference. You might want to go a step down. The next thing I'm gonna try is the output of a 2217 (rated at, 208 gph), but I'm guessing that might not be enough.


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## Ibn (Nov 19, 2003)

Depends on how it's all plumbed up. At zero head, it pushes 420 gph, but at 4' of head, it gets reduced to 243. At its max lift at 6', it's down to 87 gph. All those 90 degrees that you'll be using will reduce the flow considerably.

http://lib1.store.vip.sc5.yahoo.com/lib/marinedepot/RioSpecs.html

I'm probably gonna be putting together a close loop after the holidays, and am thinking of using one of the Mag 9s (equivalent to the Rio 3100).


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## Betowess (Dec 9, 2004)

I've had an inline DIY reactor on my outflow for over a year. Its filled with Rena Biochem stars for media and to induce some drag since its on such a small tank. I designed it to be able to take apart, but I am pretty sure I will create a leak if I open it up to clean it out, something I hope I don't have to do soon. Any ideas how long these baby's can run without clogging?? I usually keep a micro filtration pad in the XP2.

Also, I have not yet gotten around to putting in a check valve on the CO2 line. I have the Milwaukee all in one setup for the regulator. When I need to add water to the bubble counter, I have to pick up the CO2 tank and also make sure some of the CO2 line is above the tank's top, or water comes pouring backwards out the CO2 line from the reactor, making it impossible to re-connect the CO2 line and also impossible to leave the bubble couter half full of air. Needless to say, this is a small PITA. Would a check valve in the CO2 line correct this? 

P.S. This XP was quiet before I added the inline reactor and the only noise I ever noticed was some burping in the spraybar when I first hooked up the DIY reactor. I suspect this was from the last of trapped air escaping from the reactor's media. I am fairly confident the CO2 is almost completely dissolved. I plumbed the CO2 just below the point where water first enters into the reactor.


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## Ibn (Nov 19, 2003)

Reactors last a long time w/out clogging at all, especially if the correct filter media is used, since the water/gunk flows through the media before entering the reactor (another reason to put the reactor on the return/outflow side. The reactor in the picture (w/the black ABS tubing) was used on 10 gallon tank, and didn't have any problems w/clogging or CO2 dissolution. I made the second one w/clear polycarbonate to monitor what goes inside of it and when it would need cleaning. It's still too new to tell (insides look exactly the same as when I first set it up), so will have to wait to comment on that.

Definitely invest in a check valve ($10 or so) so that you don't have to deal w/that issue. It would allow you to refill the bubble counter w/out messing w/the tank. Just unscrew the top of the bubble counter, refill, and cap it off.


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## ksand (Oct 19, 2004)

Betowess said:


> I've had an inline DIY reactor on my outflow for over a year.


Could you describe the reactor? (pic would be great). Is it mounted at tank level or below? And I assume it's mounted vertically and the water flow direction is from top to bottom?


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## sundragon (Jan 10, 2011)

Awesome DIY reactor - Where did you get the plans? 



Ibn said:


> The reactor should definitely be completely filled w/water when it's running.
> 
> Not sure about the back pressure on the line, since I've always run a check valve of some sort or another. Just makes sense to spend $10 or so instead of having to replace a regulator.
> 
> The reactor is on the output side of my Eheim 2128. The Eheim is virtually silent and so is the reactor. If I crank the bubble rate up, then you can hear the bubble counter going.


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## sundragon (Jan 10, 2011)

jart said:


> other good step by step instructions include Ghazanfar Ghori's http://aquabotanicwetthumb.infopop.cc/eve/ubb.x?q=Y&a=tpc&s=4006090712&f=8006023812&m=9556098022&p=1
> 
> and wellbiz's on this site.


The link didn't work


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## inkslinger (Dec 28, 2003)

Ibn said:


>


I built this same one and I drill tap it for a 1/8th inch hose barb
and use 3/4 inch hose barbs for the end's . I might make a larger one and use a 1 inch end's. Never had a leak and Polycarbonate tubes stay clear in long run.


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## rickztahone (Jul 20, 2009)

sundragon said:


> The link didn't work


here's Rexs' version of it:
http://rexgrigg.com/diy-reactor.htm


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## Dave-H (Jul 29, 2010)

ksand said:


> I would appreciate very much if some external-reactor users would respond to this survey. I've done quite a bit of leg-work myself already: I've searched this forum, experimented with PVC and different pumps, etc, but I have a few questions:
> 
> When a well-configured reactor is working the way it should, is the chamber completely filled with water? What should the back-pressure be on the CO2 line going in.. a lot, a little, negative? What about the noise factor, both from the pump and from the reactor itself?
> 
> I would really like to hear people's comments and advice on how to do it right.


My reactor is a standard griggs model. Works perfectly. Full of water except for swirling bubbles near the top when CO2 is on. When the CO2 goes off, the bubble are mostly gone within about 20 min and usually within about 5. No noise or burps or anything. Check valve prevents water from coming up the line so I'm not sure about the back-pressure. no bubbles at all in the tank unless I put it up to 8 or 9 bps.


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## sundragon (Jan 10, 2011)

Dave-H said:


> My reactor is a standard griggs model. Works perfectly. Full of water except for swirling bubbles near the top when CO2 is on. When the CO2 goes off, the bubble are mostly gone within about 20 min and usually within about 5. No noise or burps or anything. Check valve prevents water from coming up the line so I'm not sure about the back-pressure. no bubbles at all in the tank unless I put it up to 8 or 9 bps.


Do you have an air bleed valve so you can drive out the air when priming?


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## Dave-H (Jul 29, 2010)

Nope. I just let as much water as possible flow into the reactor by priming the filter and getting some siphon going. Then there is usually about 6 inches of air pocket at the top of the reactor (which is about 8 inches above the top of the filter. I just grab the bottom of the reactor and lift it above the top - bubbles go out, new water goes in. I keep doing that until there are some nominal bubbles/gas in the reactor, and start the filter.

No issues at all. I am a big fan of 'keep it simple'.


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## Dave-H (Jul 29, 2010)

Oops I just realized that I posted an old photo. That was the original setup I tried, with an inline diffuser just before the reactor. It didn't work well and I went to the usual design, with the CO2 sticking right into the reactor.


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## sundragon (Jan 10, 2011)

Why didn't you like the inline diffuser? I've ordered one from GLA - Was it because it has micro bubbles entering the tank?



Dave-H said:


> Oops I just realized that I posted an old photo. That was the original setup I tried, with an inline diffuser just before the reactor. It didn't work well and I went to the usual design, with the CO2 sticking right into the reactor.


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## ZID ZULANDER (Apr 15, 2008)

There are units already made now. I think Aquamedic has one and Ista as well. 

This is the Ista one.


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## Dave-H (Jul 29, 2010)

sundragon said:


> Why didn't you like the inline diffuser? I've ordered one from GLA - Was it because it has micro bubbles entering the tank?


Yea the 'micro bubbles' made the tank look lke 7-up. I like my water crystal clear!


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## sundragon (Jan 10, 2011)

Ohh Nos! How long was the distance between your atomizer and the exhaust? 

I'm hoping the bubbles will be tiny/absorbed before it gets flushed into the tank. Currently I'm using a glass diffuser and the bubbles are almost invisible before they hit the surface of the water. 



Dave-H said:


> Yea the 'micro bubbles' made the tank look lke 7-up. I like my water crystal clear!


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## sundragon (Jan 10, 2011)

Where can you purchase one of these?



ZID ZULANDER said:


> There are units already made now. I think Aquamedic has one and Ista as well.
> 
> This is the Ista one.


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## newday3000 (Nov 4, 2009)

This is a whole home filter design, I built. I have an in tank pump that is dedicated to the reactor. The CO2 enters the pump in the tank which chops up the bubbles before it enters the chamber. Water leaves the chamber from the bottom and bubbles stay at the top until 100% dissolved. This works great on my 75G tank and keeps CO2 at 30ppm easily. I like this better since it doesn't restrict the flow on my canister filter all and let's me get more flow of CO2 into the tank.

I have also tried adding micron filter to the chamber to help polish the water at the same time as adding CO2. The pic below has the mircon sleave in the chamber, normally the chamber is clear.












I was testing it on my 220G tank to see how it would work.


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## Dave-H (Jul 29, 2010)

sundragon said:


> Ohh Nos! How long was the distance between your atomizer and the exhaust?
> 
> I'm hoping the bubbles will be tiny/absorbed before it gets flushed into the tank. Currently I'm using a glass diffuser and the bubbles are almost invisible before they hit the surface of the water.


The difuser was about 6 inches before the reactor. The reactor had almost no effect- the tiny bubbles just sailed through it right into the tank.

I learned/observed that:

1) the tiny little bubbles doesn't have much buoyancy and will just sail along with the current

2) the tiny little bubbles don't dissolve quickly, so they can sail around in the tank for a long time

3) larger bubbles try to float and get stuck in the reactor as they fight the current

4) as bubbles accumulate in the top of the reactor, the bash around in there and it's the agitation of the those bubbles (turbulence, impact, knocking around) that makes them dissolve quickly

Therefore, introducing tiny bubbles to the reactor in hopes of giving the bubbles a 'head start' didn't help the reactor at all. Putting full size bubbles right in to the reactor worked perfectly - no bubbles any more!

Just my experience


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