# Another CO2 Reactor DIY



## alanzhao (Mar 1, 2007)

I know many topics like this have been posted before, but I just couldn't resist to post my own. 

This is my second CO2 reactor for 75G 2nd tank. I made one couple years back and I simplified the design this time. It's not openable and has no bioballs. Total length is about 19". Most parts are purchased from Lowes except the clear PVC pipes and air line couplers. Total cost is about $15, not including the brass barbs. I assume most people like plastic, usually cost around $1 each.

I have some used clear PVC pipes left, I don't mind make new ones for trade or sale if you like it.

Ok, here are the pics:

















Sorry, pictures don't have perfect quality, I made them in a hurry.

I'll hook it up to a new XP3, which will come tomorrow.:bounce: I'll take another picture when it's in action.

Let me know if you have questions or comment.


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## EQUINOX (Nov 21, 2008)

Subscribed!
Good Luck and let us know of the CO2 concentrate in pps and the effect it has over the tank!
P.S. Can we get a "before" tank shot?


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## Chafire (Jan 6, 2010)

I like your design I actually am planning on building a reactor myself and am waiting for the clear piping to come in. I actually found a good site to get it cheap in 36" lengths. Just not sure how strong it will be but I will find out when it arrives. 

Did you use silicone to hold it together? and out of curiosity why did you choose brass barbs?


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## crossbow (Nov 29, 2009)

Something to keep in mind (for further designs).

Elbows at the top, or inlet to the reactor, tend to catch co2 bubbles. Though your smaller diameter elbow should help prevent that, it's something to keep an ear out for.


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## alanzhao (Mar 1, 2007)

I use all purpose cement to glue them together, no primer. I tried to glue the air line coupler to the PVC using Plumbing Goop, it's just not as rigid as the cement. I chose brass barbs because they're available at Lowes. I didn't want to order the plastic ones online and wait. I've been using brass for my first tank for couple years and brass doesn't seem to cause problems. Also, I could really get manly when putting clamps on them without worrying they would break.


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## alanzhao (Mar 1, 2007)

*Updates*

XP3 arrived & installed

http://www.plantedtank.net/forums/images/pGallery/pg_1071e.jpg









CO2 Reactor in action with XP3

http://www.plantedtank.net/forums/images/pGallery/pg_1070e.jpg









CO2 Bubbles get dissolved
I can clearly see the bubbles come out of air inlet and get dissolved right away.

http://www.plantedtank.net/forums/images/pGallery/pg_1072e.jpg


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## Guns286 (Sep 17, 2009)

The one I made is very similar to yours. Do you have it hooked up to the filter intake or output? Are you noticing any extra noise? After I made mine I read about adding an extra hole and valve, on the end that would be facing up, to help prime the reactor and allow you to relieve CO2 build up. Did you find that it was an issue not having one?







It's 2" pvc. About 18" long.


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## bobt2 (Dec 13, 2009)

brass fittings are ok to use in freshwater tanks?


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## alanzhao (Mar 1, 2007)

Guns286 said:


> The one I made is very similar to yours. Do you have it hooked up to the filter intake or output? Are you noticing any extra noise? After I made mine I read about adding an extra hole and valve, on the end that would be facing up, to help prime the reactor and allow you to relieve CO2 build up. Did you find that it was an issue not having one?
> View attachment 17781
> 
> It's 2" pvc. About 18" long.


You hook up to the filter output and water flows from top to bottom and goes up to the tank. I don't hear any noticeable noise. You don't need the extra release hole on top. When I first hook up the reactor to the filter I see large amount of bubble buildup, but after an hour or so these bubbles are all gone. I don't see why a 18" reactor can't dissolve 100% provided you have a decent filter like XP3 or Ehiem 22xx and BPS of 2-3(I've never tried anything higher). I prefer to have elbows so you don't bend your hose at angles. Your reactor is fine.


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## alanzhao (Mar 1, 2007)

bobt2 said:


> brass fittings are ok to use in freshwater tanks?


I heard brass can rust and release toxin. I've been using brass fitting for my first tank for couples years, I don't see any problem so far. I thought brass fittings are used for household plumbings, aren't they suppose to be safe? Most of brass fittings are lead free, is lead the toxin will release to water? I am also curious to hear what other people will say.


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## alanzhao (Mar 1, 2007)

Guns286,

I like your funnel shape reducer, where did you get it?


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## latchdan (Sep 7, 2007)

I was thinking of making a similar reactor could i use a RENA xp1 for this or is there a certain GPM to make it work?


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## Guns286 (Sep 17, 2009)

alanzhao said:


> Guns286,
> 
> I like your funnel shape reducer, where did you get it?


A website called PVCFittings.com 
They have every imaginable fitting you can think of. Shipping was fast and the prices were great. I dont know about you, but the Home Depot around here has alot of general fittings but none of the more specific stuff.


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## HEINEKEN357 (Feb 10, 2006)

Hey Guns I am having a problem with my reactor its 20in total 2in pvc I have the xp3 filter. On my bubble counter I am around 2-3bps and I am getting a lot of bubbles coming out of the spray bar. I just added my 20in 2in Uv sterilizer to the outflow of the co2 reactor and I am still getting bubbles coming out. Now when you say you are running 2-3 bps is that from your bubble counter or are you counting the bubble from inside the reactor? So you don't have any bubbles come out of that spray bar? Sorry to steal the thread


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## alanzhao (Mar 1, 2007)

latchdan said:


> I was thinking of making a similar reactor could i use a RENA xp1 for this or is there a certain GPM to make it work?


I don't know the min. GPM. If upgrading to a higher GPM filter or using a pump is not an option, I would give it a trying using 1.5" pvc pipe. I am sure there are other people have tried this before.


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## alanzhao (Mar 1, 2007)

HEINEKEN357 said:


> Hey Guns I am having a problem with my reactor its 20in total 2in pvc I have the xp3 filter. On my bubble counter I am around 2-3bps and I am getting a lot of bubbles coming out of the spray bar. I just added my 20in 2in Uv sterilizer to the outflow of the co2 reactor and I am still getting bubbles coming out. Now when you say you are running 2-3 bps is that from your bubble counter or are you counting the bubble from inside the reactor? So you don't have any bubbles come out of that spray bar? Sorry to steal the thread


I am seeing 2-3 bps from bubble counter and 4-6 bps. How long do you inject your CO2 per day? If you inject to much CO2 and have a small tank, it could be that your tank is saturated with CO2. You should lower your BPS. That's the only cause I can think of. Is it possible to post your picture?


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## HEINEKEN357 (Feb 10, 2006)

alanzhao said:


> I am seeing 2-3 bps from bubble counter and 4-6 bps. How long do you inject your CO2 per day? If you inject to much CO2 and have a small tank, it could be that your tank is saturated with CO2. You should lower your BPS. That's the only cause I can think of. Is it possible to post your picture?


Here is a picture of the reactor even at 2bps or 1.5 small bubbles flow out of the spray bar. 








Then here is a picture of my 20in reactor then go to a 20in uv sterilizer and ill still get mists of co2. What I tryed today was putting a shut off valve on the outflow near the spray bar and lowered the flow and now I don't see any bubbles but now I don't have any flow .


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## alanzhao (Mar 1, 2007)

I am also seeing very tiny bubbles coming out of spray bar. I thought that my tank is saturated because currently I don't have any plant in the tank and CO2 is not being consumed.

So I tried to turn off the CO2 injection for few minutes and I was still seeing the bubbles. I am curious that could it be the friction with spray bar causes bubbles?

The bottom line is I am not worry about the tiny bubbles I am seeing, I believe there is good amount of CO2 is being dissolved.

Your reactor looks perfectly fine. I suggest you don't worry about the bubbles, the reactor will do its job just fine.


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## Firestarter (Dec 28, 2009)

Anyone know the best place to get this clear pvc pipe. Or anyone with some left over?


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## alanzhao (Mar 1, 2007)

I've sold out mine. Try usplastic.com.


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## tyler79durdan (Jan 23, 2010)

Is it just me or are those reactors upside-down? Wouldnt you want the co2 inlet to be near the bottom so the bubbles have more distance to travel before reaching the top/ therefor contacting the water longer? Or am I missing something? I AM GREEN TO co2!, but not to engineering(WMU chemical engineering alumni). ALSO whether top or bottom, does the pressure from the co2 tank keep the water out of the air line? What about with a controller that shuts off now and then(check vavle?)?


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## alanzhao (Mar 1, 2007)

If you have high filter GPH, the CO2 bubbles might get pushed out of the reactor before they have chance to dissolve, if the inlet is near the bottom. CO2 tank does keep water out of air line, but you always need a check valve so water doesn't get into the tank when it's out of CO2.


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## HEINEKEN357 (Feb 10, 2006)

tyler79durdan said:


> Is it just me or are those reactors upside-down? Wouldnt you want the co2 inlet to be near the bottom so the bubbles have more distance to travel before reaching the top/ therefor contacting the water longer? Or am I missing something? I AM GREEN TO co2!, but not to engineering(WMU chemical engineering alumni). ALSO whether top or bottom, does the pressure from the co2 tank keep the water out of the air line? What about with a controller that shuts off now and then(check vavle?)?


WOW thanks tyler roud: I flipped the reactor over changed the holes around and now I don't get any more co2 mist :angel::angel:. I am at 3bps and don't see anything coming out of the spray bar. Guess the other reactors that I seen that has the co2 line near the top with I based mine off of mite have weaker flow. All I know its working now and thanking you again lol.


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## alanzhao (Mar 1, 2007)

From what I can see from my own reactor, when bubbles come out of air inlet they usually get pushed down about 1-2" by the flow then raised up and get dissolved. I would recommend to place the air inlet in the middle of the body just to be safe.


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## tyler79durdan (Jan 23, 2010)

Well you're quite welcome HEINEKEN357, I really was just looking at the posted pics while reading the thread and it just seemed a little off. Good luck, I hope to have the equipment you all use for you injection soon. TAXES are on the way! My 20oz bottle just looks tacky in my tank.:icon_roll


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## alanzhao (Mar 1, 2007)

Bump...


I will be making a new CO2 reactor exactly like this. I can make additional ones for sale if anybody is interested. The total material cost for this is well around $40.


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