# Co2 reactors



## Asteroid (Jul 26, 2018)

Crazyjayb said:


> Hey guys,
> I've come to realize as I evolve my tanks that I need a reactor or at least a better way of dissolving co2.
> 
> The two tanks I would be needing a reactor for would be a 40g with an eheim 2215 and a 90g with a eheim professional 3


How are you diffusing co2 now? Those tanks are easily diffused using any method. Look at this video of the large tanks and see the way co2 is diffused.


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## Crazyjayb (Jan 9, 2020)

Asteroid said:


> Crazyjayb said:
> 
> 
> > Hey guys,
> ...


They use diffusers but that is mainly for show, it gets nowhere near as much co2 dissolved as a reactor.

Currently I have a fluval diffuser on the 40 and a terrible Chinese ceramic diffuser that has long outlived it's better years


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## Quesenek (Sep 26, 2008)

Crazyjayb said:


> They use diffusers but that is mainly for show, it gets nowhere near as much co2 dissolved as a reactor.
> 
> Currently I have a fluval diffuser on the 40 and a terrible Chinese ceramic diffuser that has long outlived it's better years


It does make you wonder, in my experience the way those diffusers are setup wouldn't have worked for me on my setup.
On my 55 gallon I was easily adding in 2-4x the visual amount of Co2 out of my neo-diffuser and it wasn't even enough to change the drop checker to green let alone enough to reach optimal Co2 levels and stay stable at them.
I tried multiple ways to see if it wasn't just the way I was using the diffuser. In the intake to my AC filter, on either end of the tank, right under the flow of my HOB filter, nothing worked.

My rex grigg reactor is a much better diffusion method then the in tank diffuser and it's silent, where the neo-diffuser with how much Co2 I was putting through it I could hear the Co2 blowing out of it from the next room.

For a reactor I would go with the rex grigg design with 3" PVC and a bypass valve setup like the nilocg na advanced product. The bypass will allow you to tune the flow in the reactor without affecting the total amount of flow going back into the tank as much.


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## Asteroid (Jul 26, 2018)

Crazyjayb said:


> They use diffusers but that is mainly for show, it gets nowhere near as much co2 dissolved as a reactor.


They are for show? Why would you want to show a diffuser? Are you saying the plants are grown with a reactor and they place the diffuser in the tank? i'm not sure what your saying?

BTW I've used in-tank diffusers on all my 3 and 4 footers (72 gallons) and no problem getting optimum co2 levels. Just saying you don't need a reactor on a large tank, not that there's anything wrong with doing it.


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## Crazyjayb (Jan 9, 2020)

Asteroid said:


> Crazyjayb said:
> 
> 
> > They use diffusers but that is mainly for show, it gets nowhere near as much co2 dissolved as a reactor.
> ...


No, that is not what I am saying. What I am saying is they look pretty, conversation starters if you will. They obviously work but they have to put more co2 in to get the same level that a reactor would with less co2.


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## Crazyjayb (Jan 9, 2020)

Quesenek said:


> Crazyjayb said:
> 
> 
> > They use diffusers but that is mainly for show, it gets nowhere near as much co2 dissolved as a reactor.
> ...


Same problem for me. How much does a Rex grigg 3" reactor cost to make? Do you have a video example or of sort, I've never really understood diy reactors


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## Crazyjayb (Jan 9, 2020)

I'd like to make something like this


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## Quesenek (Sep 26, 2008)

Crazyjayb said:


> Same problem for me. How much does a Rex grigg 3" reactor cost to make? Do you have a video example or of sort, I've never really understood diy reactors


How much are you looking to spend on one? It may be better to buy one from nilocg instead of doing DIY if you're not familiar with everything.
The cost of the diy one depends largely on the tools you already have and the features you want to have on it.
If starting with no tools a standard original rex grigg reactor that is outlined here rex grigg reactor probably going to run you $35.
A 3" version with all of the reducer fittings and extras to get you down to 3/4" fittings in and out will probably run you $50
and a 3" one the same as above with a bypass will likely run you $60-65.

If you want to run a brass 3/16" fitting for the Co2 line include about $10 for the fittings needed

All of these are just ballpark numbers it may be more it may be less, and it includes the fittings, pipe, pipe cement, teflon tape for the screw fittings, and a pipe cutter. Depending on what you have and don't have already changes the price somewhat.

For a prebuilt rex grigg reactor from nilocg it runs $70, cerges runs $75, and rex grigg with a bypass $95. Yeah it's a premium, but if you have to buy everything from scratch it might not be that far off from the price of the all the parts needed when all said and done + it's built for you.


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## Crazyjayb (Jan 9, 2020)

Quesenek said:


> Crazyjayb said:
> 
> 
> > Same problem for me. How much does a Rex grigg 3" reactor cost to make? Do you have a video example or of sort, I've never really understood diy reactors
> ...


Cheap, cheap, cheap and cheaper is how much I'm looking to spend on one. I got all the tools and I'd imagine for cement I could simply use some two part epoxy? I really don't need a fancy one I just liked the features


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## Quesenek (Sep 26, 2008)

Crazyjayb said:


> Cheap, cheap, cheap and cheaper is how much I'm looking to spend on one. I got all the tools and I'd imagine for cement I could simply use some two part epoxy? I really don't need a fancy one I just liked the features


So for cheap cheap, you might just want to try your luck with the one you linked earlier and look at the comments on that product to see what people are doing with it. A reactor in my experience really needs a bypass or at least a valve at the top of it to limit the flow into it because without one mine just dumps all of the co2 out into my tank without diffusing it. Without a bypass if you just limit the flow to stop co2 blowout you're likely going to have issues with flow in the tank.

Neither the rex grigg or the cerges are cheap cheap, but they are a piece that never has to get replaced so it's a one time purchase assuming variables don't change much.

For example my 2" rex grigg reactor with all fittings without a bypass, but with a ball valve to limit flow and with a 3/16" brass fitting setup cost me $32 for just the fittings and pipe. For one with two 5/8 barb x 3/4 mpt and fittings to accommodate the setup to a canister hose add $16.


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## minorhero (Mar 28, 2019)

Crazyjayb said:


> Cheap, cheap, cheap and cheaper is how much I'm looking to spend on one. I got all the tools and I'd imagine for cement I could simply use some two part epoxy? I really don't need a fancy one I just liked the features


You can see my rex griggs style reactor in my 40 breeder journal in my signature. I built mine without a bypass because my canister filter is sized for my tank with very little flow to spare. This is also why I have 45 degree elbows at the top and bottom of the reactor instead of a single 90 degree elbow. Anyway they are pretty easy to build and lots of youtube videos are out there on how to make one. I spent a little more on mine and got a clear 2" tube because I wanted to see what was happening inside. This is not necessary but sure is nice. 

My strong recommendation is to use the correct materials when putting them together. Do NOT use epoxy when creating the reactor. Use the appropriate pvc cement. It will only run you like 7 dollars and it will mean your reactor parts will melt together performing a perfect seal vs epoxy where maybe you will be fine... and maybe your aquarium water will slowly work at it till one day in the middle of the night it springs a leak and your entire aquarium empties itself onto your floor...

By the same token if your pvc parts end up being threaded (mine are combination of fitted and threaded) then use the appropriate pvc thread goop not teflon tape. Teflon tape is for metal fittings not pvc fittings. This according to quite a few videos I watched on home plumbing. Will teflon tape give out?? No idea but plumbers use thread goop so I do as well. What is the difference between thread good and cement? Well thread goop will stay goopy and not harden. This means that you can take apart the threaded parts in the future if needed. Cement literally melts pvc fittings together and they are not ever coming apart.

Anyway considering how important a good reactor can be to an aquarium I would definitely just bite the bullet and buy the right parts to make what you want. I also would make it yourself because frankly its both easy and fun.

One last tip to keep in mind. You will need to turn your reactor upside down when first starting up. I also need to turn mine upside down after every water change (not sure if that's just my canister filter or if everyone needs to do this). So do not put it in a location where that is impossible to do.


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## Asteroid (Jul 26, 2018)

Crazyjayb said:


> No, that is not what I am saying. What I am saying is they look pretty, conversation starters if you will. They obviously work but they have to put more co2 in to get the same level that a reactor would with less co2.


Well, if you feel (and others) that you need to bump up the co2 that's different. I have nothing against reactors, all methods of co2 diffusion work, I'm just stating that you can use in-tank on any size tank effectively. Interesting note: On their 180cm tanks they are only diffusing 6 BPS and on their 3 footers 3 BPS, so something is amiss.


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## Crazyjayb (Jan 9, 2020)

minorhero said:


> Crazyjayb said:
> 
> 
> > Cheap, cheap, cheap and cheaper is how much I'm looking to spend on one. I got all the tools and I'd imagine for cement I could simply use some two part epoxy? I really don't need a fancy one I just liked the features
> ...


Alright, I've been convinced. I don't know how to check your signature on mobile but I will look into making a reactor with a bypass. Can you explain why a bypass is so important? I presume it is to make sure the flow doesn't push the co2 down and into the tank before being dissolved? 

How loud is a diy reactor, I've seen videos where they be quiet and hold it up to the reactor but I can't really hear anything bc of the lack of quality.


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## Crazyjayb (Jan 9, 2020)

Quesenek said:


> Crazyjayb said:
> 
> 
> > Cheap, cheap, cheap and cheaper is how much I'm looking to spend on one. I got all the tools and I'd imagine for cement I could simply use some two part epoxy? I really don't need a fancy one I just liked the features
> ...


Ok, for something that completely diffuses co2 I think I can live with that. 

I don't understand all these pipe and thread measurements which is why I'll look for a visual.

You know of any diy reactors with bypass valves that has pictures lol. I feel like a kid that can't read but I don't want to do this wrong.

I really want to make something like this


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## Quesenek (Sep 26, 2008)

Crazyjayb said:


> Ok, for something that completely diffuses co2 I think I can live with that.
> 
> I don't understand all these pipe and thread measurements which is why I'll look for a visual.
> 
> You know of any diy reactors with bypass valves that has pictures lol. I feel like a kid that can't read but I don't want to do this wrong


To answer the question you asked above the reason you install a bypass is so that no matter what flow you have or upgrade to you can always tune the reactor to have just enough flow to not blow out the bubbles. In some cases you may be required to install a bigger middle section from 2" pvc even with a bypass, but I think for 200-300 gph from your eheim with filter media in 2" should be fine with a bypass.

So I don't have a diy picture guide but I can lay out the exact fittings to make a nilocg version without the fitting at the bottom to feed Co2.
Starting with the reactor itself. 
All of these are schedule 40 PVC.

From the bottom up:
3/4" slip to 2" slip reducer bushing, 
2" 90, 
24" section 2" PVC pipe available in this measurement from Home depot pre cut, 
2" 90, 
3/4" slip to 2" slip reducer bushing.

From the bottom of the bypass up:
threaded barb fitting = your hose size to 3/4" npt,
3/4" 90 slip to FPT,
3/4" pvc section,
3/4" tee with a section connecting the reactor to the bypass,
3/4" pvc section,
3/4 slip fit ball valve,
3/4" pvc section,
3/4" tee with a section connecting the reactor to the bypass,
3/4" pvc section,
3/4" 90 slip to FPT,
threaded barb fitting = your hose size to 3/4" npt.

the 3/4" sections for the bypass will need to be test fit and cut to spec because I'm not sure on the length needed for those.

Dry test all of the fittings before cementing them together and be extra careful to not get cement into the ball valve area (I keep it flat on the table when cementing the ball valve so the cement is less likely seep into the ball valve area) every slip fitting needs a liberal coat of the cement and the surface of the pvc to be cemented needs to be sanded lightly to make sure it's sealed tight.

Before cementing put the top fitting on the reactor pipe and measure and mark 2" down and then follow the rex grigg reactor guide I linked above to drill an undersized hole and pull the tubing through to exactly center of the reactor pipe, just double check to make sure the drill bit used isn't bigger then the tubing. The tubing should be fairly difficult to pull through in order to make the water tight seal.


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## BOTIA (Dec 23, 2003)

Crazyjayb said:


> Hey guys,
> I've come to realize as I evolve my tanks that I need a reactor or at least a better way of dissolving co2.
> 
> The two tanks I would be needing a reactor for would be a 40g with an eheim 2215 and a 90g with a eheim professional 3
> ...


I have used and made many different reactors etc for co2 over the years. This year I bought the smaller model of this.
https://www.aliexpress.com/item/400...chweb0_0,searchweb201602_8,searchweb201603_53
It works better than any thing I have ever used. Very fine micro mist which from what I have read is easier to absorb by plants than completely dissolved plus livestock are less bothered by co2 micro mist at higher levels than totally dissolved co2. The co2 art diffuser is the exact same one just more expensive btw. Could not be any happier . Took less than 5 mons to install on the output of my canister filter and is so small barely notice it attached..

Bump:


Crazyjayb said:


> Hey guys,
> I've come to realize as I evolve my tanks that I need a reactor or at least a better way of dissolving co2.
> 
> The two tanks I would be needing a reactor for would be a 40g with an eheim 2215 and a 90g with a eheim professional 3
> ...


I have used and made many different reactors etc for co2 over the years. This year I bought the smaller model of this.
https://www.aliexpress.com/item/400...chweb0_0,searchweb201602_8,searchweb201603_53
It works better than any thing I have ever used. Very fine micro mist which from what I have read is easier to absorb by plants than completely dissolved plus livestock are less bothered by co2 micro mist at higher levels than totally dissolved co2. The co2 art diffuser is the exact same one just more expensive btw. Could not be any happier . Took less than 5 mins to install on the output of my canister filter and is so small barely notice it attached..


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## Hujeta (Jan 26, 2020)

Anyone have any thoughts on using an inline diffusor such as this one?

JBL Direct Diffuser 19/25 - Seahorse Aquariums Ltd


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## Blue Ridge Reef (Feb 10, 2008)

I just set up two that are similarly designed (Green Leaf Aquarium's diffuser). Literally just hooked them up last night so I can't speak for longevity or anything along those lines! I can say that I was able to drop pH a full point with a steady stream of gas in minutes. At first I was sure there was micro-bubble mist, but after a few hours it stopped so might have just been air in the canister filters. I am not of the belief that you want micro bubbles of CO2 in your water rather than fully dissolved CO2.


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## Crazyjayb (Jan 9, 2020)

BOTIA said:


> Crazyjayb said:
> 
> 
> > Hey guys,
> ...


Unfortunately what you sent can't be sent to the US and for some reason because of that I can't even see the product


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## Crazyjayb (Jan 9, 2020)

Blue Ridge Reef said:


> I just set up two that are similarly designed (Green Leaf Aquarium's diffuser). Literally just hooked them up last night so I can't speak for longevity or anything along those lines! I can say that I was able to drop pH a full point with a steady stream of gas in minutes. At first I was sure there was micro-bubble mist, but after a few hours it stopped so might have just been air in the canister filters. I am not of the belief that you want micro bubbles of CO2 in your water rather than fully dissolved CO2.


Similarly designed as the one hujeta listed?


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## Crazyjayb (Jan 9, 2020)

Quesenek said:


> Crazyjayb said:
> 
> 
> > Ok, for something that completely diffuses co2 I think I can live with that.
> ...


This sounds promising, do you have a picture of the completed product, I'm a very visual person


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## BOTIA (Dec 23, 2003)

Crazyjayb said:


> Unfortunately what you sent can't be sent to the US and for some reason because of that I can't even see the product




Also get it on amazon


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## BOTIA (Dec 23, 2003)

Blue Ridge Reef said:


> I just set up two that are similarly designed (Green Leaf Aquarium's diffuser). Literally just hooked them up last night so I can't speak for longevity or anything along those lines! I can say that I was able to drop pH a full point with a steady stream of gas in minutes. At first I was sure there was micro-bubble mist, but after a few hours it stopped so might have just been air in the canister filters. I am not of the belief that you want micro bubbles of CO2 in your water rather than fully dissolved CO2.


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## BOTIA (Dec 23, 2003)

Hujeta said:


> Anyone have any thoughts on using an inline diffusor such as this one?
> 
> 
> 
> JBL Direct Diffuser 19/25 - Seahorse Aquariums Ltd




Pretty same design as co2art one with an added bubble counter. 
The ceramic element is hollow so gas enters from outside the flow keeping it relatively unobstructed. Great design . Mine is now 4 months old and still working same as day 1.


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## Blue Ridge Reef (Feb 10, 2008)

@Crazyjayb in the sense that an inline ceramic disk mists gas into the water current of the output of a canister filter, yes. If the inner workings are vastly different, mea culpa for calling them similar.


BOTIA said:


> Tom Barr quote


I appreciate the correction. Besides being counter intuitive, every single time I've gassed livestock, it's been when I could see the mist and I am admittedly snakebitten. This is fresh, because the most recent time was ...when I got home from work tonight. I have it in my head that there's no way to inject so much CO2 so as that it creates a fine mist and not be nearing the danger zone, but I suppose mist can be created in water at any CO2 level. Tonight's deaths in two tanks with newly set up CO2 are entirely due my carelessness, and to make it worse I have a new controller still in the box that I wasn't patient enough to get running first. Not to sidetrack the thread, and I'm happy to discuss it in my tank journal if @Crazyjb would prefer.


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## BOTIA (Dec 23, 2003)

Here is a pic of the inner workings , it is not a disk but the same hollow ceramic tube element as the one I have. 
Brilliant free glowing low maintence design. Just make sure to put output side of canister.
Incident fish in my tank always like to play in the CO2 mist bubbles when it starts to come out. I can get ph fown quickly ..


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## Crazyjayb (Jan 9, 2020)

@BOTIA I saw that same quote from him but it didn't make much sense to me as too why. Does anyone know the reason? I can only imagine it is because the bubbles get trapped under leaves and the directly expose the leaves to pure co2?


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## Crazyjayb (Jan 9, 2020)

BOTIA said:


> Here is a pic of the inner workings , it is not a disk but the same hollow ceramic tube element as the one I have.
> Brilliant free glowing low maintence design. Just make sure to put output side of canister.
> Incident fish in my tank always like to play in the CO2 mist bubbles when it starts to come out. I can get ph fown quickly ..


I've seen those as well and been interested in trying them. I have seen much better reviews for reactors though and therefore would like to make one. I'm also not too keen on seeing micro bubbles


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## Crazyjayb (Jan 9, 2020)

Blue Ridge Reef said:


> @Crazyjayb in the sense that an inline ceramic disk mists gas into the water current of the output of a canister filter, yes. If the inner workings are vastly different, mea culpa for calling them similar.
> 
> 
> BOTIA said:
> ...


Feel free to discuss it here, my heart isn't set on a reactor and I'd like to try other things as well and an opportunity to learn more is always a good opportunity.


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## BOTIA (Dec 23, 2003)

Crazyjayb said:


> @BOTIA I saw that same quote from him but it didn't make much sense to me as too why. Does anyone know the reason? I can only imagine it is because the bubbles get trapped under leaves and the directly expose the leaves to pure co2?


Yes direct pure contact, apparently is much better.


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## BOTIA (Dec 23, 2003)

Crazyjayb said:


> I've seen those as well and been interested in trying them. I have seen much better reviews for reactors though and therefore would like to make one. I'm also not too keen on seeing micro bubbles



I don't love the bubbles either, however it easier and faster stop the ph from dropping.
With reactors there is always co2 remaining in it, do when controller shuts off it's still adding more co2 .Where difuser is on or off.


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## Greggz (May 19, 2008)

All in tank and in inline diffusers are subject to getting dirty or algae covered. So the CO2 flow rate can vary, and it will need cleaning or replacing over time.

IMO, do yourself a favor and just build a reactor. I messed around with other methods for a while, and to me they were a pain to manage. After I built the reactor, I wished I had just quit fooling around and did it from the beginning.

Personally I don't like bubbles in the tank, and my reactor leaves my water crystal clear no bubbles at all.

Besides Griggs, there are also Cerges reactors. That is what I use. Basically a home water filter housing adapted to a reactor. I use a 20" filter housing on my 120G. Brought the unit to the hardware store, and a guy helped me pick out the parts. Once I got the parts home, about 10 minutes to build it.










Research is your friend. Like most things, seems complicated at first, but the more you learn the easier it becomes.

Good luck and look forward to seeing what you come up with.


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## Asteroid (Jul 26, 2018)

BOTIA said:


> Yes direct pure contact, apparently is much better.


Yes, I was going to bring this up too, but to say something is better, in what regard? Every method works, although I think a case can me made that efficiency with full dissolution being the goal is not really true.


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## Triport (Sep 3, 2017)

Super happy with the new ones that GLA put out. Got one for my 120 and loved it so I ordered one for my 100 and installed it today. Only thing is I would not recommend having a CO2 reactor and inline heater hooked up to the same filter. But I run two filters on all my tanks so not an issue for me.

GLA CO2 Reactor added to my 100 gallon by Kaveh Maguire, on Flickr


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## Quesenek (Sep 26, 2008)

Asteroid said:


> Yes, I was going to bring this up too, but to say something is better, in what regard? Every method works, although I think a case can me made that efficiency with full dissolution being the goal is not really true.


Even in a reactor I would be very surprised if full dissolution was achieved.
There are bubble pockets that form in a reactor even after being burped and what not it's not really 100% at all.

I think that what is better is completely on the individual to decide.
In tank diffuser, you don't have to deal with plumbing and possible leaks that go along with it.
Inline diffuser, you don't have to worry about a large reactor so it allows more room under the cabinet.
Reactor, you don't have to worry about cleaning it and if setup correctly you don't have to worry about bubbles from the Co2 tank. 
A reactor will also last for basically as long as you're in the hobby, sure a bigger one might need to be made if the setup changes to a much larger size, but overall with a bypass pretty much any size pump can be plumbed in and fittings can be changed to accommodate any setup. Whereas with an inline diffuser unless they make the size needed for your hose it has it's limitations for as far as you can take it.


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## ipkiss (Aug 9, 2011)

Quesenek said:


> Even in a reactor I would be very surprised if full dissolution was achieved.
> 
> There are bubble pockets that form in a reactor even after being burped and what not it's not really 100% at all.
> 
> ...


if you're getting bubble pockets in the course of operation, i suspect you need to evaluate the balance between more flow, less co2, or introducing back pressure. or check out @Ken Keating1 's variable flow reactor

one should be able to get mininal or no pocket if you work with it enough.


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## Hujeta (Jan 26, 2020)

Triport said:


> Super happy with the new ones that GLA put out. Got one for my 120 and loved it so I ordered one for my 100 and installed it today. Only thing is I would not recommend having a CO2 reactor and inline heater hooked up to the same filter. But I run two filters on all my tanks so not an issue for me.
> 
> GLA CO2 Reactor added to my 100 gallon by Kaveh Maguire, on Flickr


Is it suitable for use in a bedroom or is it noisy? Read some reviews in Amazon staying the turbine was noisy. What's the risk of using inline heater and diffusor on the same hose? I'm thinking about doing that very thing.


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## Immortal1 (Feb 18, 2015)

Crazyjayb said:


> Ok, for something that completely diffuses co2 I think I can live with that.
> 
> I don't understand all these pipe and thread measurements which is why I'll look for a visual.
> 
> ...


Because you asked - here is my DIY reactor with a bypass valve from several years ago. I have 2 of these units in continuous operation since they were built.


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## Dirkomatic (Feb 3, 2020)

I thought I posted yesterday, but I'm a noob so what do I know?

Anyway, I bought the Sera Flore 500 with a coupon from Petco for $20... It appears to be working wonderfully.

I have read some of these threads and I still can't figure out the point of the bypass. Can someone enlighten me?

Edit: I understand the purpose of the bypass now. It took me a while...


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## Asteroid (Jul 26, 2018)

Quesenek said:


> Even in a reactor I would be very surprised if full dissolution was achieved.
> There are bubble pockets that form in a reactor even after being burped and what not it's not really 100% at all.


I agree, I actually said "with the goal of full dissolution" I think most will go to a reactor over the other methods with that in mind or at least superior dissolution.


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## BOTIA (Dec 23, 2003)

Asteroid said:


> Yes, I was going to bring this up too, but to say something is better, in what regard? Every method works, although I think a case can me made that efficiency with full dissolution being the goal is not really true.


 I should have said efficient , that is according to Tom Barre . For small tanks a diy reactor is just too big to hide ime. If you are between an intank difuser and a plumbed one its a no brainer to go to a small inline one like I posted. Diy is fun though so..have at it.


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## Asteroid (Jul 26, 2018)

BOTIA said:


> I should have said efficient , that is according to Tom Barre . For small tanks a diy reactor is just too big to hide ime. If you are between an intank difuser and a plumbed one its a no brainer to go to a small inline one like I posted. Diy is fun though so..have at it.


Funny thing is I have an UP Aqua inline atomizer (smoky gray color, same one sold under 100 different names) I bought probably 5 years ago. I never used it. I always start up with the in-tank one and am happy with the results so I never switched it out. I'm sure there are better ones on the market now, but some of these atomizers I find to be inconsistent wit certain working pressures. I also like the easy visual check of the in-tank one. Maintenance is next to nothing since I always have an extra one, plus it's one less thing to plumb inline. 

As mentioned all methods work and all have ad/dis.


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## MD500_Pilot (Dec 28, 2019)

Crazyjayb said:


> Ok, for something that completely diffuses co2 I think I can live with that.
> 
> I don't understand all these pipe and thread measurements which is why I'll look for a visual.
> 
> ...


I built two DIY reactors. The first one was not large enough and had continuous CO2 bubbles being leaked out into the tank, so I went with my version 2 and so far it seems to not only do better with dissolving the CO2 into the water, but my pH drop is much better than my first one based on 10-minute readings with a pH meter (automatically). Not sure if these are overkill, but I thought I would share:

*Version 1*









*Version 2*









I have images of it being built if you want to try it on your own, it was not very hard. Having said that, I am working on Version 2.5 now with a modification to my existing Version 2 to add a second bypass valve to more accurately control water bypass amounts.


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## Quesenek (Sep 26, 2008)

Asteroid said:


> I agree, I actually said "with the goal of full dissolution" I think most will go to a reactor over the other methods with that in mind or at least superior dissolution.


Oh yeah, sorry for the confusion I misread your post originally.
I agree, with the goal of getting the most efficient dissolution possible a reactor would seem like the most straight forward choice for a hobbyist.
However as you stated originally everything works, so what does it matter about the reactor being more efficient?
In my experience and research a reactor provides a more stable Co2 level in the water when a large amount of Co2 is being added because it isn't relying on the bubbles to diffuse themselves while inside of the tank as is the case with an in tank diffuser.

However there are counter points to this also, like has been brought up in this thread. With in tank diffusers and inline diffusers it lets the Co2 bubbles come in direct contact with the plants which allows them to pull in what is needed from that source.

And this is where the whole thing comes down to using what you want and are able to and tuning it to fit your needs as everything works and the end goal is simply to add Co2 to the water for the plants to utilize. ADA has found a way to make in tank diffusers work for very large tanks so anything is possible with some trial and error.


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## Crazyjayb (Jan 9, 2020)

MD500_Pilot said:


> Crazyjayb said:
> 
> 
> > Ok, for something that completely diffuses co2 I think I can live with that.
> ...


Your second one looks quite large, does it not work for you, is that why you are building a v 2.5? I'd certainly appreciate some pics of it being built, do you have a parts list as well?


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## Triport (Sep 3, 2017)

Hujeta said:


> Is it suitable for use in a bedroom or is it noisy? Read some reviews in Amazon staying the turbine was noisy. What's the risk of using inline heater and diffusor on the same hose? I'm thinking about doing that very thing.


Noisy the first few hours because it takes time to slowly fill with water. But the next day completely silent. There is no turbine.

Inline heater and reactor on the same filter just to me is a headache with all the tubing and hookups and can cause priming problems with your filter but I imagine that might be different depending on which filter you use. There is also always going to be at least some disruption and loss of GPH with every new thing you add. Since I tend to run two filters on all my tanks I just do the heater on one and CO2 on the other.


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## MD500_Pilot (Dec 28, 2019)

Crazyjayb said:


> Your second one looks quite large, does it not work for you, is that why you are building a v 2.5? I'd certainly appreciate some pics of it being built, do you have a parts list as well?


Well, it actually _seems_ to be working great however my design lacked a way to purge air from the top of the unit making priming it a royal (and messy) PITA. So we will be redoing the top and adding a small bleed valve to purge the air (or CO2) from the top. SH\hould only be necessary when taking it apart for cleaning. I was also toying with the idea of putting in two bypass valves as opposed to a single valve. With a single valve, you are limited in the amount of bypass you can achieve since opening the single valve simply provides a second, smaller path, but if I were to add a second valve and have my water intake come in between those two valves, I could achieve 100% reactor bypass should I choose to do so.


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## Crazyjayb (Jan 9, 2020)

MD500_Pilot said:


> Crazyjayb said:
> 
> 
> > Your second one looks quite large, does it not work for you, is that why you are building a v 2.5? I'd certainly appreciate some pics of it being built, do you have a parts list as well?
> ...


Could you simply drill a hole in the top and add a purge valve? Without having to redo the entire thing?


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## Grobbins48 (Oct 16, 2017)

Greggz said:


> All in tank and in inline diffusers are subject to getting dirty or algae covered. So the CO2 flow rate can vary, and it will need cleaning or replacing over time.
> 
> IMO, do yourself a favor and just build a reactor. I messed around with other methods for a while, and to me they were a pain to manage. After I built the reactor, I wished I had just quit fooling around and did it from the beginning.
> 
> ...


For what it's worth I second this. I build the cerges and it is fantastic. Using the 10" housing I can easily drop my pH by 1.4 or more on a 75 gallon in about an hour and a half or less. 

I have never done anything to it since the initial build, which details can be found in my journal linked in my signature (need to be on desktop to see sigs).


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## MD500_Pilot (Dec 28, 2019)

Crazyjayb said:


> Could you simply drill a hole in the top and add a purge valve? Without having to redo the entire thing?


Didn't need to redo anything really - just added this to the top:











Works great as long as you open it slowly!


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## greenthings (Aug 29, 2019)

*CO2 reactor*

I'm using the Sera 500 inline with my sump return pump. Much improved dissolving of CO2 over pollen glass.


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## Dirkomatic (Feb 3, 2020)

greenthings said:


> I'm using the Sera 500 inline with my sump return pump. Much improved dissolving of CO2 over pollen glass.


I got the same one and had to do a little work to get mine running smoothly, but it seems to work well so far.

I had to sand the inside of the "impellers" and also ensure I had enough flow out of it. When I installed my inline heater, it had a 1/2" tubing intake. That step down was enough to make the impellers stop spinning. I changed it out to 5/8" and it all runs as it should.

Also, not sure why, but this reactor should be used with 5/8" ID tubing... The amazon listing has it wrong.


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