# The Rex Reactor



## Rex Grigg

Ok, since I promised to show how to build a very simple and inexpensive reactor here is the article.










Parts List:

A - 1.75" PVC T
B - 1.75" PVC T with one 1.5" outlet
C - 1.75" PVC pipe about 18" long
D - 3/4" hose barbs
E - 1.5" PVC plug
F - 1.75 " PVC threaded plug with 3/4" thread
G - Same as F
H - 1.75" PVC cap.

Note I picked up these parts in about five minutes at the local Home Depot.

Both T parts can be straight 1.75" with no problem. If they are then E needs to be 1.75"

If you need 1/2" hose barbs then get parts F and G with 1/2" threads.

Part E is simply drilled with a small drill bit and the CO2 feed line is fed though the hole.

Here is the reactor fitted together. Note I have NOT glued anything together. If someone wants to purchase this reactor then contact me via my web site. I can put any size hose barbs you need within reason.


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## milalic

Nice design Rex. Looks similar to mine, although I could not find the plastic barbs in my area.


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## Fosty

Rex, about how long should part "C" be? Great write-up. It's not as overwhelming as the parts list for other DIY CO2 Reactors.


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## Rex Grigg

Anywhere between 12-18" long seems to work for me. I like them a bit longer so I always go about 16-20".

Those plastic barbs are over with some of the irrigation stuff.

If anyone has a problem finding barbs contact me though my web site and I can get most any size you need/want.


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## rhoymand

it seems really long. most inline reactors I see are no longer than 12". does any kind of media like bio-balls go inside?


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## Rex Grigg

Do you see any media in the picture? 

Nope. 

There is no media in the reactor. Media in the reactor slows down flow rate. Also it can clog the reactor. I have had this happen before. I took the media out of all my reactors and they work just fine.

I have never built a shorter reactor. I have no doubt they would work just as well.


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## turbomkt

One thing I'd like to note...
as with any slip couplings, you are not limited to the inlet, outlet, and CO2 being in line. You can rotate the T's any direction you want to get the combination that best fits your setup.

An example for my tank would be to have this mounted on the edge of the opening of my stand (Standard corner tank stand with the backs fairly open). The CO2 and inlet would be facing into the stand and the outlet would be on the outside edge pointing directly up the back side of the tank.

Also, Rex, is the outlet end a T to create turbulence? Otherwise, wouldn't a regular elbow work just as well?


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## Fosty

I just got the parts to make one of these, and I encountered a few simple problems: Lowes and another LHS (Local Hardware Store :wink: ) , both do not have anything with 1.75 inch PVC or CPVC pipes. Not the pipes itself or the other fittings. No big deal, just used 1.5 inch and scaled it down likewise. Also it is extreamly hard to find anything with 5/8 inch barbed fittings. I tried almost everything to make it work, and finally the LHS had one 5/8 inch barb and I used a few adapters to get it to fit right. I still can't figure anything out for the other side.

Anyways my real question is, is there any problem with using PVC cement on the connections?


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## Rex Grigg

> Also, Rex, is the outlet end a T to create turbulence? Otherwise, wouldn't a regular elbow work just as well?


I use a T so I can use a flat plug so it sits level. I would guess it also creates a bit more turbulence.

If you need 5/8" barbed fittings contact me soonest. I will be headed out to a store today that in the past has always carried a good supply of 5/8" fittings. Do you want straight or elbows? What size thread do you want?

Let me know.


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## Fosty

> If you need 5/8" barbed fittings contact me soonest. I will be headed out to a store today that in the past has always carried a good supply of 5/8" fittings. Do you want straight or elbows? What size thread do you want?


I actually just contacted someone at my LHS and they are ordering the piece for Thursday. But thanks for the great offer. BTW, do you know about the PVC cement? (See other post)



> Anyways my real question is, is there any problem with using PVC cement on the connections?


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## Rex Grigg

AS long as your PVC cement is drinking water safe you are fine.

I build a reactor and let it sit for about 48 hours. Then I just flush water though it to remove the odor.


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## wob

Nice writeup Rex, thanks once again for a straight forward, simplisitic, NO BS design and documentation.

I was planning on building a similar one today from home depot/lowes parts before reading this thread, and now it looks like it'll be even easier than I thought. 

Robert


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## scolley

Rex Grigg said:


> There is no media in the reactor. Media in the reactor slows down flow rate. Also it can clog the reactor. I have had this happen before. I took the media out of all my reactors and they work just fine.


That in itself is a great tip! Thanks Rex. roud:


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## Fosty

> AS long as your PVC cement is drinking water safe you are fine.


Sorry for all the questions, but just one more and I'll be done for good: Is the PVC Cement *nessacary*, or can it be alright and stay leak-free without it?


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## fishyface

Fosty said:


> Sorry for all the questions, but just one more and I'll be done for good: Is the PVC Cement *nessacary*, or can it be alright and stay leak-free without it?


wouldn't try it! potential for nightmare right there!


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## Rex Grigg

Fosty said:


> Sorry for all the questions, but just one more and I'll be done for good: Is the PVC Cement *nessacary*, or can it be alright and stay leak-free without it?



How else would you hold the PVC together? Duct tape?

PVC is designed to work with PVC cement. All plumbing in houses is done that way. Custom plumbing on larger tanks and fish rooms is done with PVC pipe and PVC cement.

Just give it a couple of days to cure and then flush it out and you will be fine.


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## Matak

Bookmarked!

Thanks Rex, this will replace the cheezy Boyu (read: glorified airstone) that requires 1 bps at 13° KH in a 29g tank to make 25 ppm CO2 :icon_roll


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## wob

Well I just finished building my first DIY reactor based on this thread. This was very easy and maybe cost 15$ in materials. I was able to find everything at home depot. The only compromise that I had to make was to use 1.5" PVC instead of 1.75" or 2" for lack of available fittings.

The total length of the reactor is about 24" and is attached to a 150 gallon tank, which brings me to one question: is this reactor big enough to handle this size of tank? From what I've read around here, it should be fine but I'd like a definitive answer from someone 

Also I suggest that this thread deserves a sticky for us n00bs that ask the same questions over and over!

Thanks!
Robert


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## Wasserpest

Nice simple plan, thank you Rex. roud: 



wob said:


> The only compromise that I had to make was to use 1.5" PVC instead of 1.75" or 2" for lack of available fittings.


Depending on the flow of your filter it might push bubbles out on the other end with only 1.5" diameter. It might be okay with a monster two feet reactor. :icon_bigg You will find out.



wob said:


> The total length of the reactor is about 24" and is attached to a 150 gallon tank, which brings me to one question: is this reactor big enough to handle this size of tank? From what I've read around here, it should be fine but I'd like a definitive answer from someone


If the bubbles stay within the reactor, a inline reactor can handle a 150 gal tank easily. Only thing to worry about is the distribution within the tank. If you have good current going throughout the tank it shouldn't be a problem.


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## wob

Wasserpest said:


> Nice simple plan, thank you Rex. roud:
> 
> 
> 
> Depending on the flow of your filter it might push bubbles out on the other end with only 1.5" diameter. It might be okay with a monster two feet reactor. :icon_bigg You will find out.
> 
> 
> 
> If the bubbles stay within the reactor, a inline reactor can handle a 150 gal tank easily. Only thing to worry about is the distribution within the tank. If you have good current going throughout the tank it shouldn't be a problem.



Well the pump that is driving the filteration system (raindbow lifeguard mechanical and heater module) is a quiet one 3000 rated 780gph @ 0ft of head, ~620gph @ 4ft, so the flow is pretty strong out of the spraybars, so I'm not too worried about good flow in the tank. I guess we shall soon see if it's so strong it pushes the bubbles out the bottom 

Thanks for the info, I'll post my findings later this week when I get my co2 tank filled.

Robert


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## g8wayg8r

Has anybody experimented with the depth of the CO2 inlet tube in the tee? In other words, do the bubbles accumulate at the top of the tee to form a reservoir of the gas or do you give the bubble a wild ride by injecting it directly into the stream?


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## shady3210

I assembled one of these today cost me about 20 dollars for everything(cement included). I went with 2" pvc since it was the only size I could find everything in heh. I do have a couple questions though on the c02 inlet what size drill bit should I use for that and should I use any kind of sealant around it?

Thanks btw rex for an easy to assemble reactor!

Oh and I was able to get everything at Lowes my Home Depot didn't have much of anything needed...


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## Rex Grigg

For normal air line tubing I have found that an 11/64th drill bit works fine. You want a drill bit that is about two bit sizes smaller than the OD of the tubing. Then you cut the tubing at an angle and pull it though with pliers. Start with a small hole and drill it out if you need to. You want the smallest possible size hole you can pull the tubing through.

There is no need for any sealant.


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## Rex Grigg

g8wayg8r said:


> Has anybody experimented with the depth of the CO2 inlet tube in the tee? In other words, do the bubbles accumulate at the top of the tee to form a reservoir of the gas or do you give the bubble a wild ride by injecting it directly into the stream?



I always pull enough tubing into the T to bring the tubing into the middle of the pipe.


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## Georgiadawgger

Mine is very similar to Rex's...except I use 2 in diameter pvc...and used a 1/2 inch drill bit to get the hose barb input into the side of the reactor...used a 1/4 bit to get the brass 1/8 co2 barb into the side too. 

The original reactor was made of just the clear pvc...then I realized it was too short for the power of the 2026...extended it by at least a foot with the regular pipe. 

A much more efficient reactor than the top-down versions...I think the length itself makes it more efficient. It will drive my pH from 7.1 to 6.4 with 10-12 bubbles per MINUTE. 

As far as a pocket of gas forming at the top...there has to be an initial buildup in order for the turbulence to actually break down the gas..but its minimal (not a 2-3 inch gap of air/gas).


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## Thooshe

Rex,
Have you ever used a brass fitting instead of drilling a hole in the PVC plug? I built my reactor a while back using 1.5" PVC and instead using a plug and having to worry about the possiblity of leaking, I used a 1.5" to 1/2" PVC reducing plug and screwed in a 1/2" NPT to 1/8" brass compression fitting. 

I know this does not allow for you to put tubing up into the reactor, but I never had an issue with this because I used Bio Balls in the reactor.


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## zelmo

Rex Grigg said:


> There is no need for any sealant.


Over time, doesn't airline tubing get hard? (Maybe I'm just showing my age!) If so, won't this design leak?

I currently run an airline tube to the inlet strainer on a Magnum 350. I can see how many bubbles are released and it seems to work fine with regard to not creating problems with the filter. I thought it was pretty effecient also - I had good readings on PH with only a bubble every other second. Then I found out my PH kit was WAY off. Actual 7.3 read as 6.6. I am now trying to figure out the correct bubble rate but it is going to be alot higher than before.

So, can I build a reactor similar to this, eliminate the tube in the reactor, and keep it on the intake side of the Magnum? Seems like the bubbles would get sucked down to the reactor just like they go into the canister now.


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## tazcrash69

zelmo said:
 

> Over time, doesn't airline tubing get hard? (Maybe I'm just showing my age!) If so, won't this design leak?
> 
> I currently run an airline tube to the inlet strainer on a Magnum 350. I can see how many bubbles are released and it seems to work fine with regard to not creating problems with the filter. I thought it was pretty effecient also - I had good readings on PH with only a bubble every other second. Then I found out my PH kit was WAY off. Actual 7.3 read as 6.6. I am now trying to figure out the correct bubble rate but it is going to be alot higher than before.
> 
> So, can I build a reactor similar to this, eliminate the tube in the reactor, and keep it on the intake side of the Magnum? Seems like the bubbles would get sucked down to the reactor just like they go into the canister now.



You want to put the reactor on the outflow of your can.


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## zelmo

tazcrash69 said:


> You want to put the reactor on the outflow of your can.


While that is certainly true of many canisters, the Magnum is a pull type. The way I have it now the bubbles go right down to the canister. With the impeller at the bottom there aren't any problems with air locks. I may find out differently as I get dialed in (I just found out the test kit was bad last night) but my only concern right now is efficiency. The bubble rates others are reporting are far lower than what I am getting.


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## Georgiadawgger

zelmo said:


> While that is certainly true of many canisters, the Magnum is a pull type. The way I have it now the bubbles go right down to the canister. With the impeller at the bottom there aren't any problems with air locks. I may find out differently as I get dialed in (I just found out the test kit was bad last night) but my only concern right now is efficiency. The bubble rates others are reporting are far lower than what I am getting.


I'm not sure if you understood...there should be an output to the Magnum that returns water back to the aquarium...that is the line that gets plumbed into the reactor (to churn the co2 bubbles).


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## zelmo

I understood .... the recommendation is to put the reactor in the return line to the aquarium.

OK. I can do that. I don't see what the difference is between using the intake and the return. My current system eliminates the need for a bubble counter since I see them getting sucked into the intake. I haven't had any problems from a water flow standpoint. So why can't I keep what I have, put the reactor on the return line, and eliminate the need for the CO2 line to go into the reactor? If I am having a problem getting all of the CO2 dissolved this should fix it.


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## Georgiadawgger

zelmo said:


> I understood .... the recommendation is to put the reactor in the return line to the aquarium.
> 
> OK. I can do that. I don't see what the difference is between using the intake and the return. My current system eliminates the need for a bubble counter since I see them getting sucked into the intake. I haven't had any problems from a water flow standpoint. So why can't I keep what I have, put the reactor on the return line, and eliminate the need for the CO2 line to go into the reactor? If I am having a problem getting all of the CO2 dissolved this should fix it.


If it aint broke don't fix it....if you're getting decent co2 concentration with what you're doing I'd leave it alone. The reactor design that Rex and I have are a bit different than the "conventional" ones that are floating about...those are just as well.


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## zelmo

Georgiadawgger said:


> If it aint broke don't fix it....if you're getting decent co2 concentration with what you're doing I'd leave it alone.


But that is my point. I THOUGHT it was getting good concentration. Then I found out the test kit was bad. Unless I am pleasantly surprised when I test it later I think I need to get a little better. It seemed like just adding a reactor to what I have, without the CO2 input line, would do the trick since the system I have is working fine mechanically. (IE - just add more opportunity for the CO2 to dissolve.)


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## Rex Grigg

Never have used a brass barb in my CO2 reactors. I'm not a fan of brass in constant contact with my aquarium water.

Standard airline tubing, vinyl, does get hard. But I don't use standard airline tubing.

Right now I'm using silicone to go into the reactor and polyurethane for the run.


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## P Lant

From a curious standpoint, what's wrong with brass? I thought it was more preferred than plastic. I currently have brass barbs everywhere in my piping/linning. Is there a long term thing I need to know about?  

Thanks,
Mike


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## Georgiadawgger

P Lant said:


> From a curious standpoint, what's wrong with brass? I thought it was more preferred than plastic. I currently have brass barbs everywhere in my piping/linning. Is there a long term thing I need to know about?
> 
> Thanks,
> Mike


I believe it can react with carbonic acid (co2 and water product) and release copper (a major component of brass)...but no effect from my end for the past few years.


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## Sorenweis

They also sell plastic barbed fittings with just about any dimension you may want, check out
http://www.usplastic.com/catalog/category.asp?catalog_name=USPlastic&category_name=6918&Page=1
This is what i used on my DIY reactor, which is pretty much the same as what Rex built. It has worked well over the last year, but rex is right again that bioballs will reduce flow. 
I was also playing around with the thought of putting another Tee along the reactor with a cleanout fitting so I could get in there if things get gunky. This being said, I built mine from clear 2" pvc and it can get some algae growth in there at times - I doubt this could ever happen in opaque stock. 
Cheers to DIYers


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## wob

Well I finally hooked up my 1.5" diamater 24" high version of the Rex Reactor on my 150g tank. At one bubble/sec I see some tiny bubbles leaving the spraybar. Some of them dissolve before hitting the surface, some do not.

Do you guys think it's worth building a larger reactor? I can piece together one that is 2" in diamater, 24" high and see what happens, or I can make the current one longer. Which do you think would work better?

Thanks!
Robert


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## Wasserpest

You will always look at the little bubbles coming out on the end of your reactor, wondering how much efficiency you are loosing, you will be getting angry and miserable, unable to sleep...

Me I would just redo it 2" diam. :icon_bigg


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## wob

Wasserpest said:


> You will always look at the little bubbles coming out on the end of your reactor, wondering how much efficiency you are loosing, you will be getting angry and miserable, unable to sleep...
> 
> Me I would just redo it 2" diam. :icon_bigg


Haha, that is my problem exactly Wasserpest! I will obsess over these stupid little bubbles until I get rid of them. So that means I will rebuild the reactor with 2" diamater pipe and let you guys know what happens.

Thanks for the advice! 
Robert


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## Skyfish

I have the same problem with bubbles coming out of the spray bar, my reactor is 12 inches long. So from what you are saying, 24 inches would be better? I'm sick of these tiny bubbles.


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## wob

Well I built my new CO2 reactor last weekend out of 2" PVC and it's approx. 24" long. It has certainly cut down on the flow into the tank, and I'm still getting some really tiny bubbles, but not nearly the amount I was getting with the 1.5" PVC reactor.

Any suggestions on what to do from here? I'm really anxious to finally put plants in this monster, but I want to make sure I'm doing everything right. If you all think it's OK to go ahead and throw plants in, I will! 

Thanks,
Robert


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## Georgiadawgger

wob said:


> Well I built my new CO2 reactor last weekend out of 2" PVC and it's approx. 24" long. It has certainly cut down on the flow into the tank, and I'm still getting some really tiny bubbles, but not nearly the amount I was getting with the 1.5" PVC reactor.
> 
> Any suggestions on what to do from here? I'm really anxious to finally put plants in this monster, but I want to make sure I'm doing everything right. If you all think it's OK to go ahead and throw plants in, I will!
> 
> Thanks,
> Robert


Is it upright? I have mine leaning at a 20 degree angle or so...seems to churn the co2 better and the smaller bubbles that shoot down the tube eventually make their way back up to the top and get recirculated. Another option is to add a venturi loop.


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## Skyfish

dawgger, do you have a photo of your reactor, I want to make that loop. I currently have a reactor that is 12 inches long and I feel it's not working as it should, so I want to make it longer one with Rex's design. Loop on the reactor is easy but where does the other end go?


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## wob

Georgiadawgger said:


> Is it upright? I have mine leaning at a 20 degree angle or so...seems to churn the co2 better and the smaller bubbles that shoot down the tube eventually make their way back up to the top and get recirculated. Another option is to add a venturi loop.


It was upright and based on your suggestion, I tilted it by about 30 degrees.
Now I only see tiny microbubbes every once and a while, and they almost never reach the surface. As it gets later in the day though, there seems to be more bubbles.

So it looks like titling it fixed the problem for the most part, and I'm growing impatient at this point so plants are going in this week. 

Thanks for the advice!
Robert


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## Dan Cole

*Intake Side?*

Is there some reason you don't want the reactors on the intake side of canister filter...if you're not using bio-balls, which I thought was the reason for having the reactors on outlet side....why not locate the reactor on the intake side for increased contact time?

Dan


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## Rex Grigg

If one used a straight though design there is no reason it would not work. In fact it should work quite well. But you would want no bends in the tubing at all and the reactor would need to hang on the plumbing unless you devised a bracket for it.


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## zelmo

Rex Grigg said:


> But you would want no bends in the tubing at all


Would you mind explaining why?


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## Georgiadawgger

zelmo said:


> Would you mind explaining why?


I think he means kinks...just like stepping on a garden hose outside...it will stop the flow...


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## Georgiadawgger

Dan Cole said:


> Is there some reason you don't want the reactors on the intake side of canister filter...if you're not using bio-balls, which I thought was the reason for having the reactors on outlet side....why not locate the reactor on the intake side for increased contact time?
> 
> Dan


If the reactor is designed right there is no need to put it on the intake...the co2 will automatically get sucked right into the filter...it may work...it may not, but why make the reactor then and not bubble it directly into the intake strainer inside the tank??

We put it on the outflow to allow the positive pressure churn the co2 into solution--then the co2 enriched water exits back into the tank. 

Also the immediately lower pH may not affect the beneficial bacteria inside your filter.


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## Matak

Even if there is no kink in the hose, a bend can add resistance to flow. The tighter the bend, the more resistance to flow. Also the longer the run, the more resistance to flow. Best case scenario: a short straight run. Not really possible in the real world, but a target to aim for.


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## cozmo

question, can a co2 nipple be used or do you have to run the co2 line inside?


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## Georgiadawgger

cozmo said:


> question, can a co2 nipple be used or do you have to run the co2 line inside?



??? Que? Nipple as in airline barb for the co2 gas to go into the reactor?


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## cozmo

Georgiadawgger said:


> ??? Que? Nipple as in airline barb for the co2 gas to go into the reactor?


oops, sorry. i should have clarified that. yes, the co2 barb.


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## Georgiadawgger

cozmo said:


> oops, sorry. i should have clarified that. yes, the co2 barb.


No worries ...its just a matter of preference, tools, thinking about it beforehand, etc. 

I just have a 1/8 brass barb that has been drilled into my reactor...no problems with brass and copper being leached, etc...its all a matter of how you want to set it up...you'll get the same results.


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## cozmo

cool, thanks. i'll have to try that reactor roud:


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## limey

I think I would like to try this reactor. I've been injecting co2 into my eheim 2213 for a while now at 150bpm for a 30g to bring my ph from 7.6 to 6.4 and kh of 4. I'm hoping that with a reactor, i can use a lower bubble count. Would a 2" pvc 18 inches long work well with this filter?


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## Rex Grigg

limey said:


> I think I would like to try this reactor. I've been injecting co2 into my eheim 2213 for a while now at 150bpm for a 30g to bring my ph from 7.6 to 6.4 and kh of 4. I'm hoping that with a reactor, i can use a lower bubble count. Would a 2" pvc 18 inches long work well with this filter?



That should work fine.


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## zelmo

Rex -

One of the goals of the reactor design is to slow down the water flow so that the bubbles don't just blow through, right? Given that, did you ever play around with using 3" or 4" dia pipe? I use a magnum 350 with the micron filter as my pump and after it is cleaned the flow is huge. It takes a few days to settle down and it is during that time that I think I could use a reactor.

BTW - I only depend on this for mechanical filtration; a Fluval along with the plants take care of bio.


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## Rex Grigg

I have never used larger diameter pipe. I prefer to go longer rather than wider. When you think about it it does make more sense. You want to contain the bubbles in the path of the water flow. Bubbles try and rise and water flow goes down. The larger the diameter of the tubing the slower the flow. And the more apt you would be to get bubbles rising to the top and totally out of the flow of water. 

The first reactors I built were out of 2" pipe. I doubt I will ever build another one on that diameter of pipe. The smaller diameters with longer length seem to work much better for me.


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## tazcrash69

*New Question about the Rexx Reactor*

Ok, I just assembled my DIY Co2 reacotr, and I've run it with a pump to ensure that there aren't any leaks, now my question is: HOw do I get the stink out of it? I let it run for about 30 minutes into my slop sink, but there is still the smell of the PVC cement. Do I have to just wait? Should I run it more? 

Thanks


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## bigstick120

Let it sit and dry for a few days before hook it up. Maybe a day or 2, when the smell goes away the glue is cured


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## Georgiadawgger

I just let it cure after 1/2 a day or a full day...flush it out with water and you'll be fine. The water will flush out the vapors with ease.


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## endparenthesis

I'm seeing just how cheaply I can make this (using Nutone I already had lying around for central vacuuming systems... PVC but thinner and lighter). I have no PVC cement but lots of aquarium sealant. Can anyone think of a reason that wouldn't do the trick? It could be another option for people who want to buy as few items as possible.


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## tazcrash69

Well, one thing you want to make sure of is that whatever you are using is at least drinking water safe for us humans. I'm not sure if Nutone will leech anything over time, and become toxic. I know I was told (long time ago) don't use the beige CPVC for that very reason even though it's thinner diameter. 
PVC cement don't just glue the pieces together it actually fuses them together, so that they can’t be separated in the future. Have you ever had peeling caulk in your tub or shower? PVC primer and cement is actually pretty cheap for the small cans. 
IMHO, I’m all for saving some $$, but I wouldn’t cut a cost there. I made a lot of overkill in my CO2 reactor (e.g. 2 removable end caps for cleaning, using y's to cut down on resistance instead of T's), and mine topped out at less than $20.


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## endparenthesis

Weird... I would think CPVC would be just as water-safe... it's for plumbing afterall. From what I've read Nutone and PVC are made from the exact same stuff, Nutone just isn't meant to deal with high amounts of water pressure.


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## tazcrash69

I stand corrected about the CPVC. I just found this here:
http://www.ppfahome.org/cpvc/

"Chlorinated Poly (Vinyl Chloride) (CPVC) is a thermoplastic pipe and fitting material made with CPVC compounds meeting the requirements of ASTM Class 23447 as defined in ASTM Specification D1784.CPVC applications are for potable water distribution, corrosive fluid handling in industry, and fire suppression systems"

Oh well, live and learn


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## turbomkt

I've tried aquarium silicone with PVC and it doesn't work.


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## toofazt

Yeah, silicone does not work. I tried to fix a leak in my reactor with it and no go.


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## BlueRam

endparenthesis said:


> Nutone just isn't meant to deal with high amounts of water pressure.


That would be enough to worry me. Try asking for "ends" from your local hardware store. It would be hard to spend more that $20.


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## endparenthesis

High amounts of water pressure like flowing through a house... not from a dinky filter. It's still quite solid and was just as hard to cut through.


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## eds

Some stupid questions as I put together my PVC puzzle:
Do I install this with the water and CO2 intakes on the lower end, or the top?
Do I need/want to cement screw portions (some of my caps/plugs) or just the smooth portions (i.e. the pipe into the T)?
Should I install my reactor before or after my Hydor heater?

(Sorry if these are answered elsewhere here or on Rex's site.)


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## eds

Amazing what you can find if you search!
Scratch question 1 - water flows down through the reactor.
For question 2 - no definite answer found, tho I saw 2 guys have the heater the last item in-line after their reactor, and saw no one puttint the heater between their filter and reactor.
So the only question I really still have just goes to whether I need to/should glue the threaded PVC parts.


----------



## lumpyfunk

eds said:


> So the only question I really still have just goes to whether I need to/should glue the threaded PVC parts.


just use teflon tape and that will allow you to open it if you like and wont leak.


----------



## wob

eds said:


> Amazing what you can find if you search!
> Scratch question 1 - water flows down through the reactor.
> For question 2 - no definite answer found, tho I saw 2 guys have the heater the last item in-line after their reactor, and saw no one puttint the heater between their filter and reactor.
> So the only question I really still have just goes to whether I need to/should glue the threaded PVC parts.


I use the rainbow lifeguard filter modules, quiet one pump first, then mechanical filter module, then the heater module, and then the reactor. The reactor is currently at a ~35degree tilt, and that seems to work pretty well for my setup, YMMV

Robert


----------



## turbosaurus

Happy thanksgiving everyone.. 
Quick question on length. I had to buy 1.5" PVC and it came in a 5' length. I am building two of them- one for the 180 and one for the 90. Any reason I can't just cut it in half and use 30" pieces? I have the room in the stand. Is there such a thing as too long?


----------



## Georgiadawgger

turbosaurus said:


> Happy thanksgiving everyone..
> Quick question on length. I had to buy 1.5" PVC and it came in a 5' length. I am building two of them- one for the 180 and one for the 90. Any reason I can't just cut it in half and use 30" pieces? I have the room in the stand. Is there such a thing as too long?


Its only too long if it doesn't fit under your stand...if you want it there...you can also mount it wherever you want it to. Two 30" pieces should be fine! Good luck and happy T-giving.


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## otter

Rex, is this reactor intended to sit vertically like in the picture of the one on your site, which seems to be a slightly different design? It would fit more easily under my stand if I could mount it horizontally, will be equally effective this way? Is it critical to the design to use elbows for the water in and out? You say the bio-balls decrease the flow, but don't the tees and the elbows decrease the flow significantly? Would a straight design do the trick?(mounted horizontally or vertically). I'm trying to understand the concept of this better before I build a couple. Thanks!

Dan O


----------



## hir0

I'm no pro... but it would seem to me that it makes more sense to have the reactor vertical with the flow coming in at the top and out of the bottom. Since the bubbles would rise against the flow = more contact time with the water. Horizontally I would assume the co2 would just shoot through the reactor pretty quickly. I was considering doing the same thing, but after some thought I went with vertical. Pretty much identical to Rex's design but a little bit bigger (2") with bioballs and used a barb for the co2 line. Works great. Good luck.


----------



## tazcrash69

Hey Dan, I had the same questions when I set mine up. The whole purpose is to give the CO2 bubble enough contact time with the water to totally dissolve before it comes out of the output side. hiro did a great summation. I was going to mount it horizontally at a 20 – 30 degree angle (input side higher). I was able to mount mine vertically behind the stand. I also made mine out of 2”, but skipped the bio-balls, and used Y’s instead of T’s. The biggest trick to this IMO is to have the CO2 bubble come out close to the output so that it has to run against the rushing water. My tubing runs about ¾ of the way down my reactor.


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## Rex Grigg

The reactor should be mounted vertically. I have used both straight hose barbs or elbows. 

I have built several different reactors and each one is a bit different than the one before it. The one in this article is the latest and has the fewest parts.

The simplest reactor would be a straight shot though the reactor. But you would need to be able to strap that design to something as it could not rest on the ground because of the hose and hose barb. In that design you would just use threaded caps on each end with the barb and then use a T to introduce the CO2.


----------



## [RK]

Quick question. Do you really need the T section for the CO2?

Can i just have a a PVC pipe, with threaded barbs at each end. Then drill a whole in the PVC pipe and feed the co2 into that?


----------



## Rex Grigg

You can but it's a lot harder to get a seal sometimes due to the curve of the pipe. And you kind of have to have the hole up high enough you can reach it with pliers to pull the tubing though.

But if you can get a good seal go for it. No reason it would not work.


----------



## [RK]

Yeah, im just trying ot make it as easy as it can be. its hard enough finding the parts as it is. Is there any reason why i need to full the cable through? Can i just glue on airline connected to the PVC pipe, and attach the hose to that? Or does the hose need to potrude inside the pipe?


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## Rex Grigg

Good luck trying to glue most any tubing to PVC and having it stick. 

The idea is to drill a hole smaller than the tubing and pull the tubing though for a gas tight fit. If you choose to use another method I am not to blame for water damage.


----------



## eds

Rex Grigg said:


> If you choose to use another method I am not to blame for water damage.


Am I alone in interpreting this to read that if we follow *Rex's* recommendations, he IS to blame for water damage?


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## Matak

Better get a good lawer Rex.

This guy's available:


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## [RK]

I dont mean glueing the tube to PVC. i meant glueing an airline pipe to the PVC. like this:


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## Rex Grigg

It might work.

I don't bother with lawyers. You p**s me off you deal with me.

Besides after the ODNO fire I'm not the one that should be worried.


----------



## [RK]

Any reason why it might not work?
Just wanna consider all scenarious before i build it.


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## Rex Grigg

I'm a firm believer that the KISS principle keeps Mr. Murphy at bay.

The more complicated you make something the easier it is for something to go wrong. 

Small hole and tubing........ simple

Large hole, nipple, glue......complicated


----------



## [RK]

Okay, i'll try and small hole + tubing. if that pops out or leaks. I can always drill the hole bigger and glue on the nipple  how much of the tube should i pull into the reactor?


----------



## aquaverde

Rex Grigg said:


> Besides after the ODNO fire I'm not the one that should be worried.


I missed this one. What ODNO fire?


----------



## Rex Grigg

This one. Also check out some reef forums. One would almost think that reef tanks and fire go hand in hand.


----------



## aquaverde

Yikes!


----------



## AussieTanker

> In an earlier post Rex Griggs said ...
> 
> The reactor should be mounted vertically. I have used both straight hose barbs or elbows.
> 
> I have built several different reactors and each one is a bit different than the one before it. The one in this article is the latest and has the fewest parts.
> 
> The simplest reactor would be a straight shot though the reactor. But you would need to be able to strap that design to something as it could not rest on the ground because of the hose and hose barb. In that design you would just use threaded caps on each end with the barb and then use a T to introduce the CO2.


Hiya All ....

*I'm just hoping that Rex or someone can clarify some of the points made in the various posts here in this thread about the Rex Reactor ... i have tried to summarize a few of them just so it's a little clearer ... in my mind at least ... 

are these points listed below correct?*

1. quite a few older posts from various authors about these DIY reactors suggested to arrange the reactor so that it sits on an angle - the idea being that this will increase the turbulance and hence CO2 absorption ... but i noticed on looking thru' Rex's posts again that he says several times that it should be mounted vertically if possible ... and preferably on the output side of the canister ... 

*is this the latest thinking on this issue and what has caused the change in thinking ... or doesn't it matter ... is either way just as efficient?*

2. i assume from Rex's comment that it also doesn't matter whether the barbs are straight or elbow shaped ... either is ok provided that the hoses have gentle enough curves so as to not restrict water flow too much .. and in fact the simplest preferred reactor design according to Rex is the "straight through" design ...

3.many of the earlier models that i saw from various authors had bioballs or similiar in them to help create more turbulance ... but the most current recommendation (at least from Rex) ... is definately NO BioBalls .... 

4. water and CO2 into the reactor seperately at the "top" ... water with the dissolved CO2 out of the bottom barb .. 

5. i*f you have an inline heater ... should the heater be placed before or after the heater ... i'm still a little unclear on this point ..*(just thinking back to high school science .... most of which i can't remember ! ... but something about less gas dissolves at higher temps .. or again ... is this irrelevant and it doesn't it really matter ... ) 

6. length ...basically as long as possible up to about 2 foot ......

7. use proper PVC glue ... it has two parts ..let it cure for 24 hours .... then rinse out well ... and bobs your uncle! .. 

use teflon tape on the threaded joints ..screw them down well .. i had to use a "stilsen" wrench to get the male cap to seal water tight in the female end of the T ... so taking it (the bottom one) off for cleaning is not going to be an easy task ... *did anyone else have this problem?*

finally Rex ... i wasted quite a bit of time looking in our Au home hardware type stores ( bunnings .. mitre 10 ... etc ) for all the bits and pieces ... they just didn't have most of the bits ... then on your suggestion i went to the irrigation stores ... (out my way there are dozens of them) ... bingo ... all the stuff that was needed and heaps more besides! ... too easy .... 

i discovered that the most common PVC pipe diameters are 20mm 30mm 40mm 50mm ... ie we seem to sell 1", 1.5", 2" etc ... but NOT 1.75" diameter PVC pipe and fittings ... *what would you therefore recommend as the preferred option for the diameter out of those that are readily available here in Au ... 1.5" or 2" ... *(interestingly the PVC pipe was all stamped "made in USA") ..

thats all ... sorry about the rave ... but i just wanted some help in clarifying a few things and trying to put it all in a summary form .... to make sure that i do understand it correctly ..... probably left out heaps ... but it's 3am and i'm beat ... 

*BTW ... the rex reactor is heaps more efficient at dissolving the CO2 than the JBL spiral thing that i was using ... heaps better in fact ... so thanks to Rex and everyone that has contributed to making these various designs available to the rest of us!
*
gotta go ....TIA


----------



## Rex Grigg

Wow. Long post.

1. A slight angle is no problem. I have one at an angle and one vertical. Seems to make no difference.

2. Correct. However straight barbs will not decrease water flow quite as much.

3. KISS. Keep It Simple Stupid. Had the bio-balls in one reactor took them out. They would actually accumulate enough gunk to restrict water flow. And I noticed no difference in the efficiency of the reactor.

4. Correct

5. Beats me. I doubt there is going to be that much difference in water temperature.

6. Correct

7. Correct

Yeah I had to use an adjustable wrench to tighten things down.

If I had to choose between the two I would go with the 2".


----------



## [RK]

*AussieTanker* - I tried looking for the parts in bunning too. And mitre10 and about 4 Plumbing Supplies stores, and no luck. Youre from Sydney too, can you let me know which irrigation store you bought yours from? And the rough cost of each item?

Also, have you tried to find clear PVC? I managed to get clear acrylic pipes. But since its not PVC or Downpipes, the PVC joints dont fit onto it  Its either too loose by 1mm or too tight by 1mm to fit. Sucks, cause i really wanted to use a clear pipe, so i can see if its disolving or if there is a big buildup of Co2 in the reactor.

Also, would you be able ot post some pics of your reactor? Please


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## Rex Grigg

If it's not dissolving you will be able to hear it. Same for a build up of gas.


----------



## [RK]

How do you hear it? What do you look out for?


----------



## AussieTanker

> RK said -----
> 
> AussieTanker - I tried looking for the parts in bunning too. And mitre10 and about 4 Plumbing Supplies stores, and no luck. Youre from Sydney too, can you let me know which irrigation store you bought yours from? And the rough cost of each item?


yes .... i spent several afternoons driving to various Hardware stores ... Plumbing Supply companies ... even tried a few welding companies etc ... it took ages ...all of them sell the PVC pipe ... but NONE had the End Caps, T Pieces, and the elbows and straight barbs etc .... i think that i visited almost every hardware store btwn windsor and parramatta ... without success ...

i happened to be reading Rex's posts again ...(for about the 10th time) .... and i noticed this comment that he made earlier on ..



> Those plastic barbs are over with some of the irrigation stuff.


i must have read it dozens of times ... but it never really sunk in until about the 15th time! ... talk about slow learner :icon_redf ..

i live out at Castle Hill, in the NW Hills area .... I'm not sure if it's just because of all the large acreage properties out here, or all the market gardens, or maybe fear of bushfires etc .. but we have quite a number of large irrigation supply shops in this area ... and they all pretty much have all the stuff that you need ....... i also found them pretty helpful ... just print out a picture of rex's reactor in the very first post in this thread ... or sketch it out ....take it in with you and show them what you want ... in my experience they will help you pick out all the bits pretty quickly ...i think that they are used to irrigation guys coming in and throwing a bit of a "problem job" at them and then picking out bits to solve the problem ... 

the pvc pipe usually comes in about 6 metre lengths .... but both places that i visited were quite happy to sell me a shorter length of PVC ... they already had a pipe that had been cut down .... 

i can't remember how much it all cost ... but basically the larger the diameter the more the various bits cost ... i bought the 2" stuff and i think the T pieces were about $3 a piece ... the primer and glue/cement are about $8 each can for the smallest size ... but once you have it... i imagine it would last for quite a while ... all up i think that it cost me about $25 for the pipe and bits and pieces and about $15 for the primer and cement .. 

try the yellow pages ... but if you still have problems locating someone in your area pm me ....

as for knowing if it's dissolved and the noise etc ... i have absolutely no clue about that at all ... so i will leave that answer to someone else who actually knows what they are doing ..... i'm just kind of following the experts blindly! ... i don't have a digital camera to post a pick sorry ... but it looks pretty much exactly like Rex's example on post #1 of this thread ... except "messier" ... with bits of glue smears everywhere ... i'm not a very good DIY'er ... but i'm trying to learn! 


hope that this helps you a little RK ....

regards
aussietanker

ps ...BTW the irrigation stores that i visited also sell bulkheads that can be used for aquariums ... i didn't ask about clear pipe ... i think that clear pipe could lead to more algae .... but i am due to go back to the irrigation store next weekend ... i will ask if you like ... just pm me if i forget to post the answer for you ....


----------



## [RK]

After i saw your post i did a search in yellowpages and i also noticed that a LOT of the stores are around the Hills/Dural area. Kinda makes sense cause it is sort of a farm area (for very very rich people. hehe). I live in Blacktown, so its not too far me. I'll go check out some places in the weekend. I dont think clear PVC exists in Australia. which sucks a lot. I've asked sooo many major piping companies and none knew about them.


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## nitromad

Rex Grigg said:


> Part E is simply drilled with a small drill bit and the CO2 feed line is fed though the hole.


would it make any diffant if you put an airstone on end of the co2 tube??? or am i thinking stuid thing ?


----------



## Fosty

nitromad said:


> would it make any diffant if you put an airstone on end of the co2 tube??? or am i thinking stuid thing ?



It would be fine for a while, but it wouldn't really help all that much and it would get clogged up eventually creating problems (especially if its glued shut and you cannot take apart the reactor to clean it). It really isn't nessacary for any reason that I can see.


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## AussieTanker

Hiya all again ...

i wasn't quite sure of this post is totally appropriate to this thread .... if not please PM me and i will "relocate" it ... (or mods .. please feel free to move it ... and apologies in advance) 

i'm still working on trying to get all the "bugs" ironed out of my Rexx DIY CO2 reactor ... 

by way of background i made my rexx reactor out of 2" diameter PVC .... cause that's all that i could get at the time .... its also a little on the long side at about 24" .. 

after making it i discovered that it was just a tad too long and wouldn't quite fit under the cabinet ... :icon_redf ... so i had to put it under the cabinet on a slight slope .. rather than vertically as recommended by Rex ...

*a slight problem has arisen and i am wondering if anyone else has experienced this issue with inline DIY reactors and if so ... how did you solve it?

i had a real tough time getting my canister filter (i have a fluval 304 on a 32 US gallon tank - heaps of flow ... almost too much i think) to start or prime after installing the reactor for the first time a few weeks ago .... it seemed to badly airlock or something ... it took ages to get it going and i'm not real sure exactly how i did it now ... but i just thought that it was due to the fact that it was all new .... 

tonight i decided to cleaned the fluval again after installing an inline heater (hydro) ....and struck the same problem ...but even more difficult to get it going ... it took nearly 2 hours, and i ended up snapping the little gizmo that you use to prime the canister by pumping it up and down :icon_redf ... now i know why people buy an eheim!

is this a common problem with the inline reactor .. or have i just got an error in the way that i am doing it ... how have others that had this issue fixed it? ...
i remember once on a big swimming pool filter (a kind of cartridge thing that was about waist high) that there was a little knob or screw up at the top that was used to "bleed" all the air out of the system after cleaning the cartridge ... could this be applicable here ... or is it a bit too complex for DIY ? ..*

DIY can be sooo frustrating sometimes :icon_conf .... but i am determined to keep at it and keep learning and improving ... altho i have to confess that i feel a little discouraged right now ... hopefully tommorrow will be a brighter day :icon_bigg 

any help or ideas are greatly appreciated ...

thanks again
aussietanker


----------



## tazcrash69

I had a very similar problem when I installed my RR(tm). 
I think that air in the reactor was keeping the filter from running af full capacity. 
The bleed valve would work for my problem but in keeping with the KISS methodology, and avoid anything that could cause a leak, I found an easier fix:
Tip the reactor to bleed it. I tilted the reactor so that the output higher than the input and lot of air shot out of my spray bar, and everything worked great after that. (fingers crossed)

Hope this helps.
Walter


----------



## AussieTanker

Hi and thanks for the quick response ... 

i presume that you mean that you tilted it so that the bottom of the reactor was higher than the top of the reactor ... 

or did you mean that you lifted the whole reactor gizmo up so that the bottom of the reactor was higher than the top of the spraybar or water outlet ... sorry to ask ... but i'm just trying to make sure that i understand it fully ... 

i did try tilting the bottom of the reactor so that it was above the top of the reactor several times .... many times in fact ... but that didn't seem to fix it ... it just seemed to be totally locked up ... do you need to do this lifting repeatedly?

is there another way? ... 


or could it just be a particular problem with my design ... or cause my canister is too "powerful" for the tank and is causing too much pressure build up ... aaarg ... so confusing!

anyway ... anymore feedback is greatly appreciated ...


----------



## tazcrash69

No problem. 
you were correct on your fisrt assumption
I tilted the reactor so that the reactor output was higher than the reactor input. Image doing a rotate 180 on it. 

I just did it once, and it purged the reactor of all air. My reactor is similar in dimension, but I have mine on an eheim 2026 (lots more flow). Mine was running, just not getting the flow I should have. It sounds like your filter might be airlocked, not the reactor. is there water going into the reactor? any coming out? 

I had an old Fluval 304 (round can), and getting that thing primed was a PITA!.
I used to have to fill the canister, and tilt it to get it running. 
If you can try tilting your canister so that the water level is at the impellor to bleed it. After you start getting some water through, then tip the reactor to bleed it.


----------



## Matak

Could it be that your CO2 is causing the airlock? All that gas buildup with no place to go may be just enough to cause your fluval to cavitate. Just a WAG. If it is, try disconnecting the CO2 line whenever the pump is off.


----------



## AussieTanker

again ....thanks for your help on this ....

no ... there seemed to be water coming into the canister from the tank ... but there didn't seem to be any water coming out of the canister into the reactor ... but i NEVER had any problems priming this particular canister prior to installing the reactor ... and then the inline heater today ...

...but it's very late here now (3am) ... gonna leave it 
'til later ... perhaps i will wake up and realize that it was a dream!    

thanks for your input ... i really appreciate your suggestions ... all help is appreciated


----------



## tazcrash69

Not a problem, that's what the forum is for. 

guess it's back to work for me.


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## [RK]

Okay, mine is done  havent tested it yet. And i made it really simple. I'll keep it up by using cable ties, thats why i didnt make a flat bottom.


----------



## Matak

Wow, looks store bought. Nice job roud:


----------



## [RK]

thanks  the top fitting was sealed perfectly. looks awesome. the bottom one i accident twisted a bit while the cement was wet, so it kinda smeared a bit. but im pretty happy with the way it looks. i just hope its long enough to fully dissolve the co2 without any tiny bubbles coming out. Its 40mm thick and 18 inches long.


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## Matak

Is that regular airline tubing RK? If it is, you might want to upgrade to silicone tubing, as it doesn't break down from the CO2 gas nearly as quick. Pretty cheap (at least around these parts) too.


----------



## [RK]

Yup, its silicone tubing


----------



## yeldarb

AussieTanker:

Is your reactor on the suction side of your filter? My DIY reactor is, and I had a similar problem. 

To remedy it, I installed an additional quick-disconnect on the water hose between the the water intake from the tank and the reactor. There is an existing quick-disconnect at the filter (Eheim 2213), so the reactor can be isolated from the rest of the system and be disconnected. I have a plastic pot scrubber in my reactor to create turbulence and to act as a pre-filter. Since this needs to be cleaned periodically, I have made it quite simple: unplug the filter, shut off the quick-disconnect valves and disconnect them. I then empty it of water and unscrew the threaded coupling on the reactor and clean it and reassemble. 

Prior to reattaching the reactor to the tank, it must be completely filled with water, or the prime is lost. Once filled I reattach the quick-disconnects, open the valves and plug it back into the power. 

Seems to work well for me.


----------



## AussieTanker

Hiya all...



> RK said....
> Okay, mine is done havent tested it yet. And i made it really simple.


That's a GREAT looking Reactor RK .....I'm sure that it will work just fine .... well done ... :thumbsup: 

in reference to your PM ......to get rid of the "after glueing" smell ... i just followed some advice seen here earlier .... 

after assembling and gluing the reactor.... i just left it out in the fresh air for a few days and then flushed some tap water thru ... put the caps on lightly ... shook the water around and then tipped it out .. did that a few times to get rid of the smell ... worked fine .... hope that helps ...

also ....



> yeldarb said ...
> Is your reactor on the suction side of your filter? My DIY reactor is, and I had a similar problem.


... it's kind of nice to know that i wasn't the only one with the problem .... thank you for your advice and suggestions ... it's appreciated .. as it still is an issue for me ... once it primes it all runs beautifully and it's much more efficient that the old Hagen spiral tube think that i had before ... i am quite confused by this issue cause i actually wondering if the problem is on the "suction" side as ...

1. when i finally got it going last time (after about 3 hours - no exaggeration - of trying to prime it ) .... the thing that seemed to work was when i took the long inlet tube that acts to suck the water down into the canister off the inlet flex hose ... this left the intake hose opening just a couple of inches below the surface of the water .... somehow that seemed to enable it to prime .... this suggests to me that it is something to do with the "suction" side 

however ...

2. when trying to prime it previously i opened the quick release connections (the point where the hoses enter the fluval canister) over a bucket ... water immediately and freely flowed into the bucket thru the suction side hose ... so that seems to suggest that there isn't a blockage on that side .... 

these two things seem to me to be contradictory ... so any further ideas are welcome ...

my reactor is on the "return" side of my canister as recommended by "The Rex" ... ie it's between the canister and the point at which the water flows back into the tank ... it's just before the new hydor inline heater that i recently installed .... i don't think that this particular problem arose until i installed the inline heater ....i certainly can't remember it being an issue then ... but i am not sure if that's just coincidence .... or if the heater has in fact somehow changed the dynamics of the flow ... 

are those quick disconnect fittings eheim fittings yeldarb? ... 

i think that i understand how it's working for you ... i wonder if those fittings will fit either of my fluval hoses or the plain tubing that i have used in my setup? ... i will look into it ... thank you ...

while it's working brilliantly once it's primed and running ... it's become an absolute horror to clean the filter and get it all going again ... i am really hoping that i can figure out what is wrong 'cause i think that otherwise the Rexx reactor is absolutely brilliant ... 

thanks all for your continued input ...

regards
aussietanker


----------



## yeldarb

Yes they are Eheim fittings, but there are similar made by Fluval also. Any quick-disconnects with shutoffs, sized to your hoses, should work.

The key that I have found is that water stays in all lines, including the filter when the reactor is removed. When the reactor is replaced, full of water and with the valves closed, there is virtually no air in the system to create the airlock.


----------



## Jerm

Hmmm... 100 some odd posts.. no need to sticky this, it'll never go away!


----------



## Oqsy

I've got a few questions about my almost finished rex reactor. I'm going to be using about 14-16" of 2" PVC with the elbows, caps, etc, just as shown in the first post (with the obvious exception of larger pipe diameter, and also no reducing tee, everything is fitting the 2" pipe.)

Questions:

#1 I'm using Flexible PVC from the irrigation section at Lowe's for my current CO2 setup (it's black, which is nice for my internal reactor since my bg is black). It's not as flexible as say vinyl or silicone. Would it be advisable to just remove the flexible pvc from the setup and use something easier to seal the drilled hole with (ie vinyl), or does anyone think that the flexible pvc will have enough elasticity to seal off the tiny hole? FYI, the run from the CO2 cylinder to the reactor will be less than 2ft. 

#2 I've gathered that this reactor is meant to be vertical, but I wonder... does this unit stand on it's own? no wiggling? I'd LOVE to just set it in the bottom of the tank stand, but fear that a gurgle in the filter might give it enough of a rattle to tip it over. Strapping it to the inside of the stand isn't really a problem, I'm just lazy and tired of convincing my wife that I need to go to Lowe's/HD *again*. 

#3 I see the mention of 3/4", 1/2", and 5/8" barbs for filter tubing. I'm going to be using this reactor with a 2217. This is my first Eheim, and I'm not sure of the tubing size that comes with the filter. I got the 1/2" barbs on a hunch from threads searched here for "eheim hose" and "eheim tubing", but never saw a direct measurement in inches, only mm. Should the 1/2" barbs work, or should I return them for another size?

I think that's all for now. 

Thanks,
Oqsy


----------



## Oqsy

well, i went ahead and assembled the reactor tonight so that it will be thoroughly cured by the time my filter gets here. (jan. 4th according to ups). I decided to try using the flexible pvc, and it looks like it works just fine with the drill-and-pull method, although I used a slightly larger bit than I would for standard airline tubing due to the fact that it was just too thick and rigid to pull through the 11/64" hole without breaking. also had to heat it up with hot tapwater to get it pliable enough to squeeze through, but now it looks tight. my only concern is that instead of being sealed on two fronts (inside of drill hole and outside of drill hole where the airline tubing bulges to make the seal), this is only sealed on the outside of the pipe because pulling this less elastic tubing through the hole just smashed the tube up tighter and there was no spring back to the original diameter. Only way to see for sure is a leak test with soapy water I suppose... I wonder if pvc cement would work on flexible pvc... anyway, I'll post results and a pic when done. Thanks again Rex for setting the pace 

Oqsy


----------



## banderbe

Rex, I built one and hooked it up.. now my Co2 tank isn't even turned on right now but everything is plumbed and the cannister filter is running. All I would have to do is turn on the Co2..

So why am I seeing lots of little bubbles coming out of my spray bar? I thought maybe it was just air from inside the PVC and maybe it is but it has been over two hours since I hooked it up and turned in the cannister and little bubbles are still coming out.. but where are they coming from? They are not Co2, the Co2 isn't turned on!

Help!

I put my reactor at 30 degrees past vertical so the inlet is at the top left and the outlet is at the bottom right.. 

BTW, the reactor was constructed from 1.25" PVC, and is 18" long. Also I had to use PVC 90 degree street elbows instead of the elbowed hose barbs because they only had straight hose barbs.. but it built fine and looks slick.

Thanks!!!

Edit: Problem solved, the air was all gone this morning. I think I could have turned the reactor upside down so the output was above the input to "burp" it right away but either way no more little bubbles.. Now tonight I'll turn on the CO2 and hopefully no MORE little bubbles!


----------



## Fosty

> So why am I seeing lots of little bubbles coming out of my spray bar? I thought maybe it was just air from inside the PVC and maybe it is but it has been over two hours since I hooked it up and turned in the cannister and little bubbles are still coming out.. but where are they coming from? They are not Co2, the Co2 isn't turned on!


It's probably just the air. It can take a while to get it all out.


----------



## Oqsy

for what it's worth, the pvc cement *does* work with attaching flexible pvc to the regular white stuff. i wouldn't recommend using very much at all, as pvc cement actually melts the pvc a bit to make the bond, and too much would just eat into the flexible pvc tubing to the point that it is mechanically unsound. I took a q-tip and just dabbed some on the outside of the reactor right at the entry point of the flexible pvc CO2 line. within an hour or so it was obvious from a small tug that it had bonded far better than I expected. so here's yet another option for those of you looking for ways to insert and attach the CO2 line into the reactor. btw, the flexible pvc i use is black and is sold in lowe's in the drip irrigation isle. internal diameter is a bit tighter than standard airline tubing, but the OD is identical from what I can tell (eyeballing them side by side). 

Oqsy


----------



## banderbe

Fosty said:


> It's probably just the air. It can take a while to get it all out.


Yeah the air was all out this morning..

I think for anyone else interested that if I would have tipped the reactor upside down so the output was above the input it would have "burped" it and that air would have come out right away..


----------



## zelmo

banderbe said:


> I think for anyone else interested that if I would have tipped the reactor upside down so the output was above the input it would have "burped" it and that air would have come out right away..


If your return to the tank is below the water line all you need to do is siphon the water back through the reactor.


----------



## JayDBaltimore

Is it ok to use brass fittings anywhere? I know copper is a no no.


----------



## imeridian

No, don't use brass.


----------



## Fish'InMN

Why not?


----------



## imeridian

There are plenty of reasons already given in this thread, but suffice it to say why use something that can be a risk to the inhabitants when plastic barbs are readily available, if not locally, online?


----------



## Fish'InMN

Settle down, I agree with you. The 'reasons' have nothing to do with what has been said in this thread, which is very little, and that is why I asked.

Here is the main reason I try not to use brass in freshwater aquaria: Brass leaching zinc in freshwater. Note specifically... 
_"Alloys with more than 15% zinc may be susceptible to a corrosion process called "dezincification." Zinc is leached out of the surface, leaving a *weak, porous copper structure*. Dezincification occurs in freshwater and is more likely to occur in *softened water with high carbon dioxide levels* or in water containing chlorides. High temperature, crevices, and corrosion deposits promote dezincification."_

The brass fittings available in most hardware stores are "leaded-yellow brass" alloys that contain upwards of 35% zinc. I have personally seen dezincification take place on gate valves, ball valves, and barbed fittings from big-box stores, most often on the (internally) exposed threads.

I hope that is enough reason not to use brass for our applications, especially this nice reactor. :thumbsup: 


Cheers,
Marty


----------



## JayDBaltimore

Sigh, I got all of my parts at Home Depot. They have var fewer little PVC parts than Lowes. But I have a workable system. Putting it together tonight. Thanks for the tips, and this thread!


----------



## BiscuitSlayer

JayDBaltimore said:


> Sigh, I got all of my parts at Home Depot. They have var fewer little PVC parts than Lowes. But I have a workable system. Putting it together tonight. Thanks for the tips, and this thread!


You might want to check out Ace Hardware stores for future projects. I was surprised to find that a little Ace store had a far better selection than a large retailer like Lowes. Ace sells 90 degree plastic barb fittings whereas Lowes doesn't (that I can find).


----------



## forddna

Can anybody post pics of this or similar reactors plumbed?


----------



## jaidexl

forddna said:


> Can anybody post pics of this or similar reactors plumbed?


How bout a diagram? Made one for someone last week. Can't take a good picture because it's hidden behind a mess.


----------



## forddna

That's how I thought it went. It's hard to read instructions and picture it exactly (for me, anyway). Thank you!


----------



## Natty

I have it in my tutorial video

http://mochimochi.vidiac.com/video/9eb0e871-5075-44df-8820-9b2c01317595.htm


----------



## eyebeatbadgers

forddna said:


> Can anybody post pics of this or similar reactors plumbed?












Mine heats the water too, except now the external pump is inline after the reactor.


----------



## RAGEo2

My experience,

Switched my reactor from my Magnum canister to a used Eheim 2217. First problem I had to remove the 3/4" inch barb to 1/2" for the Eheim line to fit. 

Had a hell of a time trying to prime it. Ended up priming one part at a time using a bucket to catch all the water droppings. Literally took me 2 hours and the flow was bad out of the spray bar and the canister made tons of noise. 

Easy fix I thought, Tilted the filter and reactor and many burps but still no better pressure. Checked all lines and fittings for leaks and noticed a small leak in the airline feeding the reactor. Removed the cap and DUH I used regular airline and it had stiffen the airline causing a leak. Fixed then reattached and re primed . +2 hours

The canister still made a lot of noise and the water pressure was slim. So I took some media out of the canister to try and see if that was the issue but the pressure was still low. I thought maybe the 22" x 1.5" PVC pipe was to big for the 2217 to fill with it's 1/2" tubing. +1 hour

But then it dawned on me or should I say my wife. While I was fixing the problem she setup the Magnum back up and when she was done and saw me struggling said " you know the magnum is very quite now that you took the reactor off the line. Maybe it's the reactor or something *stuck in it*." 

*SHOOT ME*>>>>>> The freaken *Bio-balls*. I recall them as being quite small and fit perfectly in the t bend. The thought did cross my mind a few months ago when I built the thing that it may clog the reactor but hey I read it some where in the forum that they where a good idea. To late to think about it. Went to bed with that in back of my mind.

Then this morning I was looking at the canister and decided to unplug it and replug to see if the noise would go away. But it was even worse as if it had no water in the line. So I disconnected the output from the reactor and decided to use the quick shut off valve as my priming valve to get the canister filled and the air out. It took about 1 full minute fully opened to get all the air out. 

I suspect that the Co2 has been filling up the reactor on top and since the output of the reactor is suspected of being clogged. It is causing the gas to flow backwards into the canister ( law of less resistance) . Sounds a bit weird but hey what else can it be since the thing was working , slow but working last night before we went to bed. I have my Co2 on a timer that kicked on about 2 hours before I noticed what I suspect to be gas in the canister. It could be air but how would it get that much air in their after being fully functioning, pulling and tossing water last night.

So I am almost positive that it is clogged and now I am off to the store to get some more PVC and building a new reactor. I could just cut the one I have and reuse it after removing the balls but I have nothing better to do today. Besides the first one has some massive purple all over the pipe so I will make this one a bit neater and maybe even smaller.

The moral of the story...

* KISS - DON'T USE SMALL BIO BALLS!!!!*
*Priming is easy* when you use quick shut off valves to get the air out of the lines. Just be careful!
*Never* test your Co2 projects at night. Though nothing happened to me. Had the gas been on all night I _may have_ found myself swiming in my living room.:fish:


----------



## manofmanyfish

*Good GOD that's better than 3 years worth...*

and I still have questions.

I am trying to figure out if most people use their primary canister filter to drive their reactors or if they have a second independent filter (pump) to drive the reactor. If you choose a secondary pump/filter for the reactor, its size would not have anything to do with the size of the tank as it would the size of the reactor...correct? After all the idea is to have enough water pressure to somehow maximize the CO2 dilution process? So what is a good size filter for this?


----------



## Wasserpest

I think most of us don't buy a canister to specifically drive a CO2 reactor like this one. I'd say it is not too hard to size this reactor to any canister filter. The stronger the canister filter, the wider diameter should be used for the reactor.

Basically, if the diameter is too small, bubbles will go through the reactor and come out of the outlet. If too large, there isn't enough turbulence and gas MIGHT collect on top of the reactor.

So I would choose a canister (or second canister) based on your tank needs, go a bit larger, and then add the inline reactor.

For example, if you have a 70gal tank, and currently use a Filstar XP3, and find that there is not enough flow and filtration, you might add another XP2 or even XP3. If there is currently plenty flow, just add the reactor to your existing canister. It does reduce flow just a little bit.


----------



## manofmanyfish

Happy Thanksgiving (again).

I have a 70g tank with a Fluval 405 and a HK-2 to improve circulation. Currently would like to remove items from tank. IE. heater and AM 500 reactor. I don't think the Fluval would have enough umph to put the heater and external reactor inline. So, I could put the heater on the Fluval and add a second filter for the DIY reactor. My limiting factor is going to be space below the tank in the cabinet.

Any recommendation


----------



## Jeff5614

Since space is an issue you could try a needlewheel pump instead of another canister filter for your CO2. Now if I can only find that thread.... Found it!

http://www.plantedtank.net/forums/equipment/75891-needle-wheel-co2-diffusion.html


----------



## Wasserpest

Happy Thanksgiving! :fish:

I think you are on the right track. A second filter is a good idea, it extends the time between cleanings, and of course adds more flow and filtering capacity.


----------



## manofmanyfish

Jeff5614 said:


> Since space is an issue you could try a needlewheel pump instead of another canister filter for your CO2. Now if I can only find that thread.... Found it!
> 
> http://www.plantedtank.net/forums/equipment/75891-needle-wheel-co2-diffusion.html


This looks like something entirely different. I am not sure I understand this apparatus without further study, but it sure looks interesting. Am I correct that this device would be used instead of the CO2 reactor?


----------



## Jeff5614

You are correct. It's just another method of diffusing CO2 into your tank. CO2 is injected prior to entering the pump which has a needle wheel impeller that breaks up the CO2 into very small mist-like bubbles.


----------



## fish dork

Here's a picture of mine, before I added the hose barbs to either end. The PVC pipe is 2" and the entire reactor is 18" long. I mounted it on a slight angle to the cabinet wall. Works great at 3 bps. I used a little irrigation peice for the input of the CO2 line. It has 2 inputs; they are both threaded and I left one with the cap on.


----------



## lemuj

fish dork said:


>



That piece look interesting. Where can someone find that little thing u got there? I have the plug for the T part just not sure if i'm drilling a hole for the co2 tubing or i'd get me a 3/16 hose barb. Your's another option. I hope u didn't get them ship from the US, as that'll be tough for me(us here in Canada) to find them locally.


----------



## fish dork

Umm... I'm in Canada and I bought it from the hardware store. RONA to be exact. That little piece was in with the irrigation stuff. The threaded end was 1/2 inch so I found a piece of PVC that had a half inch threaded fitting. I ended up using straight barbed fittings on either end for the in/outputs. The other difference was I used a threaded piece on the bottom so that the bottom can be removed for cleaning.

I think that piece is made by dripmaster.


----------



## fish dork

I should maybe add that mine is mounted as shown in the pic, the T fitting is near the bottom. I used that as the input for the CO2 so the bubbles are rising from the bottom against the flow of the water which goes straight in the top and out the bottom.


----------



## imeridian

Typically you would want to inject CO2 at the top of the reactor close to where water enters, the standard design for the reactor. 

I've tried it both ways and injecting at the bottom provided significantly more undissolved bubbles at the outflow. 

I know somewhere in this thread someone did all sorts of fancy math to show how bubbles rise and dissolve and all that, but the math and the overwhelming amount of anecdotal evidence didn't jive. Anecdotally the bubbles dissolve as they are forced down the reactor from water pressure/current, not as they rise through the water column.


----------



## fish dork

Doh! I stand corrected! I had this conversation with someone already and I ended up with the injection point being at the top not the bottom. So... I'm actually running it like you just mentioned, it's mounted upside down from the picture I posted earlier... please disregard that last post. (I'm on nightshift and must not have had a coffee yet!)


----------



## lancermit

*Here's my 8 year old version*

I built this from scratch many years ago. It's still running on my 55g Discus tank.

 DIY CO2 Reactor


----------



## imeridian

Heh, alright. You'll have to let us know how your bit of injection hardware works out. I had a hose barb and injected through that, but then switched over to pulling the tubing through a hole as Rex recommends. I want to say the ordinary tubing without the barb worked better, but I think they're basically on par with each other.


----------



## fish dork

Well so far, so good. I get very minimal tiny bubbles in the tank at 3 BPS. Almost completely broken down by the reactor. I mean very minimal bubbles escape. Maybe one or two every so often. Does it have anything to do with the injection method? I don't know as I have not tried it the other way. But this does seem to be working well, so why mess with it?


----------



## Scorpion

Tagged!


----------



## fat_man_25

the pipe comes in 24" piece is that to long or should i cut it down?


----------



## rickztahone

so after reading this whole thread my only question is, do any of you know the standard hose size for an xp3? i believe it's 5/8 but i would like to make sure before i go buy the parts. also, i have an inline heater and was wondering if anyone else has such a setup and has recommendations as to whether to put it before or after the reactor. for those with an xp3 and a reactor, are there any priming issues? or more noise? thanks for your help


----------



## jaidexl

Yes, the filstar is 5/8". I couldn't find barbs locally, got mine at savko.com.

Can't help with the heater, sorry.


----------



## fresh.salty

I used 3/4" barbs and a cup of hot water. Only way to get them off is cut the hose. I found 5/8" at Ace but for some reason even with teflon tape the fitting would bottom out before it was tight.

As far as priming, that's all done on the intake side of the filter. So the filter will prime OK but it takes a while to evacuate all the air from the reactor.


----------



## jaidexl

Yeah, it's amazing what I've accomplished with scolding hot tap water.


----------



## ocelli

I am putting one of these together to run inline with my canister. Does it matter if I place it before or after the filter.


----------



## rickztahone

It needs to go on the output side Ocelli


----------



## Jowlz

Would putting a 90 degree elbow in the middle of this reactor affect performance? The layout of my cabinets would involve lots of extra plumbing but if I put a 90 elbow in the middle it would fit very well...


----------



## rickztahone

Jowlz said:


> Would putting a 90 degree elbow in the middle of this reactor affect performance? The layout of my cabinets would involve lots of extra plumbing but if I put a 90 elbow in the middle it would fit very well...


Imho I believe that might restrict flow significantly


----------



## Jowlz

rickztahone said:


> Imho I believe that might restrict flow significantly




Thanks. I should have been a little more clear. I was wondering if it would effect the way the CO2 was dissolved into the water. The two pumps I am using on this tank set up are too powerful for the size tanks. I was planning on 2 much bigger tanks but got a deal I couldn't turn down on 2 75's. I am having to install a return to the sump as is, so I can control flow to the tanks. The restriction will actually be welcome. Both pumps are rated at 1100 gph and are going only to a 75 gallon tank each....


----------



## rickztahone

Jowlz said:


> Thanks. I should have been a little more clear. I was wondering if it would effect the way the CO2 was dissolved into the water. The two pumps I am using on this tank set up are too powerful for the size tanks. I was planning on 2 much bigger tanks but got a deal I couldn't turn down on 2 75's. I am having to install a return to the sump as is, so I can control flow to the tanks. The restriction will actually be welcome. Both pumps are rated at 1100 gph and are going only to a 75 gallon tank each....


in that case it might work. do you have a pic?


----------



## Jowlz

I don't have a picture of the plumbing but the tank set up is in my profile and in the DIY stand thread. Thanks.


----------



## Dave-H

I am really interested in this type of reactor. But, I am concerned about flow.

My Eheim 2236 is rated at 185 gallons per minute, and my tank is a 54 gallon corner bowfront. Does anyone have an opinion about whether I would lose significant flow if I installed this type of reactor? I need all the flow I can get!


----------



## idex

Dave-H said:


> I am really interested in this type of reactor. But, I am concerned about flow.
> 
> My Eheim 2236 is rated at 185 gallons per minute, and my tank is a 54 gallon corner bowfront. Does anyone have an opinion about whether I would lose significant flow if I installed this type of reactor? I need all the flow I can get!


I didn't notice a significant decrease in flow with my 2236 after installing a diy rex style reactor.


----------



## Dave-H

Bingo! I was hoping someone else out there would have the 2236 working well with the rex style reactor


----------



## Dave-H

Another question: 

I like the simplicity of the design, is the CO2 intake hole sealed in some way? Or is it just the pressure of the tubing sticking through the hole that keeps it sealed? 

That seems like a weak point to me. Is it as simple as just drilling it then pushing the tube through to make the seal??


----------



## idex

Dave-H said:


> Another question:
> 
> I like the simplicity of the design, is the CO2 intake hole sealed in some way? Or is it just the pressure of the tubing sticking through the hole that keeps it sealed?
> 
> That seems like a weak point to me. Is it as simple as just drilling it then pushing the tube through to make the seal??


No extra seal needed... just drill the hole a little smaller than the diameter of your tubing and you're good to go.


----------



## ojustaboo

Building the rex reactor, but in the UK, the parts are hard to source.

I can do it if I use 50mm pipe. 

Only thing is, the cheapest way would be to use a 50 - 40mm elbow at the top, then a 40mm - 3.4" reducer, then a barb into that.

Would that affect anything?

rough picture of the top bit below




Thanks


----------



## Gplus

Just as a future reference to anyone building this.....1.75 INCH PVC DOES NOT EXIST. You have to either downsize to 1.5 INCH or go up to 2 INCH. After building my own I can vouch for it and say it works AMAZINGLY well but I believe that the Piping Rex uses in the picture is 1.5 INCH not 1.75inch. .....Also when it came to drying time I was extremely impatient and completely fed up with my red sea in tank reactor. I only let the thing dry for about an hour before I couldn't resist the urge to hook it on and see it work. Everything was fine no leaks at all. The cement and sealer are designed to dry within a few minutes so if your in a rush you don't have to wait days for it to dry Imo.


----------



## jaidexl

Gotta run it through a Rex Grigg PVC Expander. :bounce:


PVC cement doesn't take long to dry. When I fix pool equipment I give it maybe 10 minutes then fire her up.


----------



## Gplus

"Gotta run it through a Rex Grigg PVC Expander." :icon_mrgr Do they sell those at Hope depot?! 

In all honesty I really love the rex grigg reactor it works amazingly well for a DIY. I think its my favorite piece of equipment (because its diy lol). Wasn't bashing just wanted to save people some confusion. 10-15 mins is plenty! Just rinse it out and your good to go! 


Forgot to say it before but a big thanks to Rex Grigg for the great design!


----------



## wakesk8r

I just recently built these out of 2" clear schedule 40.
cool being able to watch how it all actually works


----------



## jaidexl

blue-ram said:


> I just recently built these out of 2" clear schedule 40.
> cool being able to watch how it all actually works


Awesome. Please take video of that!


----------



## alan j t

nice view, 
i plan on using my rex reactor again. 
my dilemma is, should i use a pond pump or an old fluval 305 to push the reactor. its going on a 75?


----------



## jaidexl

Man I got an XP3 on a 75 and the reactor just about kills it too much. It's enough flow to make me too lazy to replumb but I would definitely consider a closed loop for it or a bigger filter.


----------



## Brownthumb07

I made one for my 125. The reactor itself is 4 feet tall and its connected to the input of my fx5. I used 2 1/2 inch clear pvc for the main body and standard 2 1/2 inch white pvc couplers to 1 inch reducer. I had to turn the flow down on my fx5 to keep the microbubbles out of my filter and out of the tank even with a 40 inch drop. Works like a charm though. I made the mistake of over tightening the threaded hose barbs so they were sucking air. Took the two hose barbs off and redid them. All good now.


----------



## jaidexl

Brownthumb07 said:


> I made one for my 125. The reactor itself is 4 feet tall and its connected to the input of my fx5. I used 2 1/2 inch clear pvc for the main body and standard 2 1/2 inch white pvc couplers to 1 inch reducer. I had to turn the flow down on my fx5 to keep the microbubbles out of my filter and out of the tank even with a 40 inch drop. Works like a charm though. I made the mistake of over tightening the threaded hose barbs so they were sucking air. Took the two hose barbs off and redid them. All good now.


It should be mounted to the output so no bubbles ever pass the filter. Not good for the motor to add obstruction to the filter inlet, plus co2 can corrode meterials inside the filter.


----------



## Brownthumb07

Bubbles arent making it to the filter now. Regardless of where it is mounted co2 gets to ur filter.


----------



## jaidexl

Brownthumb07 said:


> Bubbles arent making it to the filter now. Regardless of where it is mounted co2 gets to ur filter.


In gas form or do you just mean saturated into the water? Co2 _gas_ is corrosive. If that reactor is after the filter and microbubbles are making it through the aquarium and back into the filter, then the reactor is not working properly. I can push 5bps into a 15" long, 1.5" PVC Rex reactor and get absolutely no microbubbles in the tank. That's presumably close to 100% saturation.


----------



## Gplus

jaidexl said:


> It should be mounted to the output so no bubbles ever pass the filter. Not good for the motor to add obstruction to the filter inlet, plus co2 can corrode meterials inside the filter.


It doesn't matter either way man! If your reactor is built right you shouldn't have to worry about micro bubbles! I've have mine mounted on the intake of my xp2 for about a month now. It works awesome. The filter helps distribute the co2 more evenly before it gets shot out.Your argument backing is the fact that some people say they AIR LOCKED their filter by using a reactor on the intake side. Plain and simple if your reactor air locks your filter than its not working at any rate close to 100% effectiveness! Also worth mentioning that mounting the reactor to my intake did little to nothing to my flow rate!


----------



## jaidexl

Gplus said:


> It doesn't matter either way man! If your reactor is built right you shouldn't have to worry about micro bubbles! I've have mine mounted on the intake of my xp2 for about a month now. It works awesome. The filter helps distribute the co2 more evenly before it gets shot out.Your argument backing is the fact that some people say they AIR LOCKED their filter by using a reactor on the intake side. Plain and simple if your reactor air locks your filter than its not working at any rate close to 100% effectiveness! Also worth mentioning that mounting the reactor to my intake did little to nothing to my flow rate!


Obstructing the intake of a filter is a sure fire way to shorten the life of the motor. That's just a fact that you can't argue with since the whole world already knows. If there's something about me that makes everything I type sound like a lie, well go talk to any pump manufacturer. I'm done with this thread, I simply stated facts to help others out, I don't need to argue with people over common sense.


----------



## Brownthumb07

There isn't an obstruction to the intake of my filter. Everything is as big or bigger than the factory hose that came with the filter. The flow is ridiculous with the reactor on the intake side. I have a ball valve on my output. That is how I manage the flow.


----------



## Gplus

jaidexl said:


> Obstructing the intake of a filter is a sure fire way to shorten the life of the motor. That's just a fact that you can't argue with since the whole world already knows. If there's something about me that makes everything I type sound like a lie, well go talk to any pump manufacturer. I'm done with this thread, I simply stated facts to help others out, I don't need to argue with people over common sense.



I don't want to argue. Just wanted to give good mention to what I've found works best for me. When the reactor is on my output side the canister flow goes WAY down and the top of the canister tends to fill with a small pocket of air. Not enough to airlock but I notice the water level goes down a bit. Mounted on the intake works great! Little to no flow reduction and my filter says completely full of water. I honestly wasn't trying to argue and don't think we think everything that you say is a lie your getting defensive for no reason. We've all herd the stories that back what you said, but for me the intake side is the way to go! My advice to anyone not liking the reactor on your output and it dissolves co2 close to or at 100% then Give it a try on the intake. If you don't like it switch it back, simple as that! 

Nothing wrong with a little spirited conversation! Wouldn't call it arguing.


----------



## alan j t

so heres the setup, what do you think


----------



## Leebee

I am also considering putting a reactor on the intake side. Should I be concerned about the acid effect of the co2, or is this nothing to worry about? I used to keep reef tanks, calcium reactors use injected co2 to dissolve calcium carbonate. I never heard of any problems with eroded impellers from co2, and these units work with recirculating water pumps!


----------



## Jeff5614

Leebee said:


> I am also considering putting a reactor on the intake side. Should I be concerned about the acid effect of the co2, or is this nothing to worry about? I used to keep reef tanks, calcium reactors use injected co2 to dissolve calcium carbonate. I never heard of any problems with eroded impellers from co2, and these units work with recirculating water pumps!


CO2 + Eroded Impellers = Internet Myth


----------



## Aquaticfan

Jeff5614 said:


> CO2 + Eroded Impellers = Internet Myth



This be TRUTH........ See we actually agree on more then one thing. lol. 


But Id have to say its a better idea if possible to run a reactor on the output side of the filter. My reasons is it will get more gunk and potential crap inside it on the intake, thus making it dirty and less effective and the potential to get a blockage in a hose fitting. With it on the output your filtering that out. That and with it being gravity feed. If your siphon breaks or you have an issue on the intake side like a blockage or plug from garbage it can cause damage to an impeller at least, and id rather be injecting Co2 after my filter so my filter gets to suck in some of that good O2 from gas exchange at the surface its bringing in to give my Bio media good O2 inside the filter... not just the max of Co2 it can take in. But those are my opinions..


----------



## Jeff5614

Aquaticfan said:


> This be TRUTH........ See we actually agree on more then one thing. lol.
> 
> 
> But Id have to say its a better idea if possible to run a reactor on the output side of the filter. My reasons is it will get more gunk and potential crap inside it on the intake, thus making it dirty and less effective and the potential to get a blockage in a hose fitting. With it on the output your filtering that out. That and with it being gravity feed. If your siphon breaks or you have an issue on the intake side like a blockage or plug from garbage it can cause damage to an impeller at least, and id rather be injecting Co2 after my filter so my filter gets to suck in some of that good O2 from gas exchange at the surface its bringing in to give my Bio media good O2 inside the filter... not just the max of Co2 it can take in. But those are my opinions..


Now we're going to have to agree on another thing darn it. I prefer it on the output side also but mostly just to keep it cleaner. I've also wondered if you would have CO2 levels higher in the filter than the rest of the tank if you put the reactor on the input.


----------



## Leebee

Thanks guys, great answers. I worry that the flow will be reduced too much on the output side of my canister. I don't think it would get that blocked from dirt on the input side, no more than any other part would.


----------



## Leebee

Another question, I don't think we have 1.75 inch pressure pipe here. I can get 50mm, or 30mm, 1.75 inch is about 43mm, we don't have that in Australia. My eheim canister is rated at 1050lph, any ideas on pipe size?


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## TheNamelessPoet

so am I to understand (sorry for the dumb question) that the co2 is entering from the LOW end and water is flowing from the HIGH end to the LOW end?

I am far from a plumber and fomr wome reason this setup doesn't seem to do anything lol. I know it does its raved about I am just trying to understad the basic physics of it...


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## Mark Fisher

This design provides for a counter-current flow, i.e., the CO2 bubbles are going up while the water is being pumped down. The CO2 will dissolve quickly in a counter-current flow.


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## TheNamelessPoet

Mark Fisher said:


> This design provides for a counter-current flow, i.e., the CO2 bubbles are going up while the water is being pumped down. The CO2 will dissolve quickly in a counter-current flow.


Ok it makes a little more sense now thank you. Ug I feel like I am in a fog today.


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## Aquaticfan

It's actually just basic physics. Gas rises water pressure forced down. The 2 going against each other with enough contact time causes the co2 gas to dissolve in the water and it then will exit the reactor. 

You want the co2 inlet just about midwayish down the reactor. To low and the gas will escape into the tank to high not enough contact with the water to dissolve. Length of the reactor and diameter depend on flow of water. More flow larger reactor. I would say 2" at 18" is a good start point for most.


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## herns

Does Rex still exist in TPT? His last post was 2010. His web has a forum too but was ghost town.


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## Aquaticfan

Hey Herns.

Nope, Rex has been missing for sometime. Last info I had on Rex was health issues caused him to no longer be involved in the hobby. His website will be up til it expires. But no one should try to buy anything from his site as you won't get it. 
sent from my HTC EVO 3d


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## newbieplanter

I was looken for this for a bit finally found.


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## Psycofc1

Anyone know if the bottom has to be a 90 for this to work or will a straight through pipe work?


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## norbot

Straight should work, but it could depend on the length of the tube and your flowrate. You want contact time with the water and if your flow is too fast and/or the tube too short, you'll end up with bubbles in the tank.

I switched from straight to 90's because the dang thing was so awkward under my stand it kept kinking the tubing, but if you install it wisely, that shouldn't be an issue


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## Psycofc1

Flow rate is probably in the 200's I have a sunsun 304a, its printed rating is 525 I think. Tube length is 24in will be mounted at a slight angle.


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## newbieplanter

wakesk8r said:


> I just recently built these out of 2" clear schedule 40.
> cool being able to watch how it all actually works


How did u get the lights inside the tubes if they are internal?


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## inkslinger

newbieplanter said:


> How did u get the lights inside the tubes if they are internal?


he use clear see thru pvc? I made one with polycarbonate tube stays clear for a long time. cost a little more.


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## jeffdenney

What if I built one and left the co2 inlet out of it and just used my up inline diffuser upstream of the reactor??? Would that help it dissolve any better?? I have the inline diffuser now but Im tired of a million little bubbles in my tank lol.

Thanks

25 gal.-api renastart xp1 anf xp2- 2 custom spraybars with diy inline heater and water change valve (so key!)-odyssea-4x24w t5ho. 4in raised.-injected co2 via up inline diffuser-florite and sane substrate.-java fern-amazon sword-marsilea minuta-water wisteria (crappy)-dwarf hair grass-anubias afanzeli (spellcheck)-telanthera cardinalis-10 tiger barbs-6 glofish tetras-7 otocinclus -1 german blue ram. females died.-2 albino corydoras. I know need 6
ei dosing and 6 hours light 100%


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## OVT

Don't see the point: if the reactor is built right, it will dissolve 100% of co2. No bubbles.

v3


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## jeffdenney

OVT said:


> Don't see the point: if the reactor is built right, it will dissolve 100% of co2. No bubbles.
> 
> v3


Really? I didnt know they worked that well. Maybe I will just pull the inline diffuser off and build me a nice reactor/inline heater/ water change ball valve setup.. kill three birds with one stone. Lol thanks for the help

25 gal.-api renastart xp1 anf xp2- 2 custom spraybars with diy inline heater and water change valve (so key!)-odyssea-4x24w t5ho. 4in raised.-injected co2 via up inline diffuser-florite and sane substrate.-java fern-amazon sword-marsilea minuta-water wisteria (crappy)-dwarf hair grass-anubias afanzeli (spellcheck)-telanthera cardinalis-10 tiger barbs-6 glofish tetras-7 otocinclus -1 german blue ram. females died.-2 albino corydoras. I know need 6
ei dosing and 6 hours light 100%


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## aquarium hippy

I built one a few weeks ago and I have my co2 maxed out with no micro-bubbles only nice pearling plants. 


Sent from my iPad using Tapatalk HD


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## yobofofas

Just built my Rex Reactor today but can't pick up my C02 tank till monday. Bummer. But I do plan on getting it hooked up inline to make sure my flow isn't too limited. Did any of you have flow issues? If so is it just as easy as getting a more powerful pump?


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## yobofofas

Hooked up the reactor today and it works great. No flow issues at all. I went with 2" PVC and an 18" length. Seems to work great. There are a few micro-bubbles every once and a while but I'm pretty happy. Thanks REX.


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## yobofofas

I'm curious; I switched out my spray bar for a clear PVC spray bar and I'm wondering if the increased flow will cause outgassing. I've got the spray bar just below the water level pointing up at a slight angle to create surface distortion. Am I just completely out gassing all the CO2 my Rex Reactor has mixed into the water?


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## Chronados

yobofofas said:


> I'm curious; I switched out my spray bar for a clear PVC spray bar and I'm wondering if the increased flow will cause outgassing. I've got the spray bar just below the water level pointing up at a slight angle to create surface distortion. Am I just completely out gassing all the CO2 my Rex Reactor has mixed into the water?


It depends on how much surface agitation you are creating, but no, it should not be a problem. My outflow creates quite a bit of surface disturbance (without breaking the surface though) and I don't find I need to crank my CO2 particularly high.


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## zodduska

I decided to rebuild and recommission an old Rex reactor. 

I didn't think the injection through the brass barb was completely ideal so I placed two small o-rings around a roughly 1.5" long piece of co2 tubing, then super glued that on the inside part of the brass barb to extend the injection point to the center of the water flow inside the reactor. I found a can of "hammertone" Krylon Fusion at hobby lobby on clearance for three bucks, I think it turned out kind of nice. 

I blasted hot water through the reactor with a python for an hour after letting the PVC glue and paint dry for two hours outside before hooking it up. I added activated carbon to the tank to absorb any acetone that may be leaching into the water, I also put some purigen in the filter the day before.. the stuff is amazing.


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## newbieplanter

I am wondering how people are measuring the level of CO2 in their tank after this unit is installed, an how long after hooking it up do u see the changes? If u use a drop checker did it turn green or stay green within mins/hrs, or did u have to wait a day or so. Those with bubble counters did u have to turn the output down or up?


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## jaidexl

newbieplanter said:


> I am wondering how people are measuring the level of CO2 in their tank after this unit is installed, an how long after hooking it up do u see the changes? If u use a drop checker did it turn green or stay green within mins/hrs, or did u have to wait a day or so. Those with bubble counters did u have to turn the output down or up?


1.drop checker

2.co2 level start to rise immediately but it takes a little while for the DC indicator to change, maybe an hour? Never timed it.

3.not really understanding the BC question, it is just for reference and doesn't really mean anything, you use the DC reading to fine tune your output, then the BC as a visual reference for the particular tank.


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## newbieplanter

jaidexl said:


> 1.drop checker
> 
> 2.co2 level start to rise immediately but it takes a little while for the DC indicator to change, maybe an hour? Never timed it.
> 
> 3.not really understanding the BC question, it is just for reference and doesn't really mean anything, you use the DC reading to fine tune your output, then the BC as a visual reference for the particular tank.


I know all these items we have to measure CO2 on our tanks is just an estimate or to reference, as I'm reading the posts others state that they are now havering to turn down to a lower bubble count than before. I'm askin cuz when I had the Ista max on my tank I actually had to turn my pressure/output up same as when I had one of those bootleg diffusers off eBay on my tank not speakin about the output on reg. but output on the NV.


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## jaidexl

The Rex reactor built the same way Rex did achieves 100% diffusion, or at least to the human eye it does. So if you're replacing a diffuser that creates visible micro-bubbles then yes, you may need to drop your output a bit.


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## gnatnog

I know this thread is ancient, but i'm interested in building one of these reactors. I'm hoping someone has the plans still since the links don't seem to be working anymore?


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## tylergvolk

I'm gunna build one of these. I don't know why I have waited so long.


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## flight50

I bought parts last summer to build one but never got around to it. Since my current project got underway with construction, I went ahead and went with the Cerges Reactor. It's in place but not operational at this time. Considering I never returned the parts for the Rex Reactor, I will go ahead and construct the Rex reactor and install it on my 125g plant only grow out tank. I'd like to be able to compare the two.


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## AquaLady86

I cant see it!


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## funlearning

Really basic question - Should the water enter the reactor at the top or bottom? Thanks


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## Nlewis

funlearning said:


> Really basic question - Should the water enter the reactor at the top or bottom? Thanks


The top.


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## funlearning

Thanks - kind of an embarrassing question to ask on this forum.


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## vanish

I'm about to build one of these. Does anyone want me to document the build?

Alright then, no log!


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## Morecowwbell

could someone repost plans for this bad boy!

thanks


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## natemcnutty

Morecowwbell said:


> could someone repost plans for this bad boy!
> 
> thanks


Sure: https://rotalabutterfly.com/rex-grigg/diy-reactor.htm


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## chayos00

Just made a "monster" sized one! 4" pipe by 4' tall. Why so big you may ask? Because I had the pipe already. (Turns out I really had sewer pipe and not PVC, but since I already bought the fittings shipped to me, I went to Lowe's and got the 4" PVC.)









Sent from my Pixel XL using Tapatalk


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## Morecowwbell

Thanks for the link and pic. Very helpful!


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