My Inverted CO2 Reactor Build

mike

Guru Class Expert
Jan 13, 2012
169
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16
Quebec, Canada
As the title says, this is my Inverted CO2 Reactor build. I'm hoping to combine two very good reactor designs, those being the Cerges reactor and the Rex reactor, to make a better one, although I can't be certain until I build it and use it for a while.

Unlike most, if not all, other reactors I've seen, the water/CO2 enters from the top through a series or elbow and exits from from the top or bottom through more elbow. The main complaint I have seen with most reactors is the loss of flow. I'm hoping my design will maintain full flow, because there is almost zero head pressure and only one modified tee in the reactor to create turbulence.

Since it's hard to explain what I am going I have put together a video explaining the design and the parts.

[video=youtube_share;DGJDrcAWyFM]http://youtu.be/DGJDrcAWyFM[/video]

Although I would have loved to use clear PVC to build this reactor, I was not able to find any in Canada, and to order from FlexPVC would have cost about $120 for just the 24” clear PVC. My entire build, with grey schedule 40, is $130. For people in the US, all this can be ordered from FlexPVC for about under $100 or a little more if you want clear PVC.

Mike
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
Hi everyone, I'm back with 3 more videos, since I cannot post 3 video's in one post I will make 3 posts

In this first video I will explain a little more about the inlet of the reactor. It's a schedule 80 fitting and I will explain why.

[video=youtube_share;Sm3DE-tCL_M]http://youtu.be/Sm3DE-tCL_M[/video]
 

mike

Guru Class Expert
Jan 13, 2012
169
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16
Quebec, Canada
In this second video I will show you the tee that has been cut and the partially assembled reactor.

[video=youtube_share;e8rr1DPpa50]http://youtu.be/e8rr1DPpa50[/video]
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
And the third video is the assembled reactor and the final internal 3/4 inch pipe and tee.

[video=youtube_share;mw0-Ul-ygDo]http://youtu.be/mw0-Ul-ygDo[/video]



I think this reactor is an excellent reactor for people who have their sumps a floor below their tank. They can make the reactor longer. Also, it does not have to sit on top of the pump like I have done, you can attach it to a wall and run some pvc or flexible pipe from the pump to the reactor.

Mike
 
Mar 20, 2013
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How is this reactor superior than any of the other inline reactors available commercially for 1/10 the cost?

Also, I was not entirely certain how the design was superior. Can you explain that to me?
 

PK1

Guru Class Expert
Oct 7, 2005
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Pennsylvania
Mike,

I think the double pass is a great idea, it essentially doubles the duel time plus the effect of your Tee on the top, let us know how it works.

Regarding the Tee, what if you capped the ends and then drilled holes at opposing 45 degree a facing down? This way you would get a vortex effect in the outer sleeve and mix things up a little more before discharge.
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
Solcielo lawrencia;116699 said:
How is this reactor superior than any of the other inline reactors available commercially for 1/10 the cost?

I can't say I've ever seen any $10 to $13 reactors that are 20+ inches long and 4" in diameter. Please send me the link, I will be more than happy to buy it.

I believe I've taken care of the issue many people have with oxygen and Co2 buildup that is often seen in large high velocity reactors by adding the outlet at the top and attaching a small pump to remove the gas build up. Also, the way the tee is beveled and pointing slightly down causes a vortex in the reactor that increases the dwell time. You don't often see this in large reactors. In any case, like many in this hobby we are always trying to improve upon previous designs, I would like to know what you believe would make a better reactor? If I can incorporate it into my design I will.

Regards,

Mike
 

mike

Guru Class Expert
Jan 13, 2012
169
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16
Quebec, Canada
PK1;116701 said:
Regarding the Tee, what if you capped the ends and then drilled holes at opposing 45 degree a facing down?

Hi PK1,

Before I bought everything I was thinking of doing what you suggested but there is not enought room to put caps, instead, I added just enought pipe so that the pipe is almost touching the sleeve and then I made the beveled cuts pointing slightly down.

I started it up last night but my camera battery was dead, I will take a video of it this weekend and post it.

It took about 5 minutes for all the air to be purged out. I saw at lease a 75% reduction in the bubbles in the tank, I believe to get to almost 100% dessolved CO2 I would have to use a smaller pump, right now I'm using a 950 gph pump. Before I change the pump I'm going to put pot scrubbers down the length of the internal 3/4" pipe and see if that helps.

Mike
 
Mar 20, 2013
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mike;116708 said:
I can't say I've ever seen any $10 to $13 reactors that are 20+ inches long and 4" in diameter. Please send me the link, I will be more than happy to buy it.

I believe I've taken care of the issue many people have with oxygen and Co2 buildup that is often seen in large high velocity reactors by adding the outlet at the top and attaching a small pump to remove the gas build up. Also, the way the tee is beveled and pointing slightly down causes a vortex in the reactor that increases the dwell time. You don't often see this in large reactors. In any case, like many in this hobby we are always trying to improve upon previous designs, I would like to know what you believe would make a better reactor? If I can incorporate it into my design I will.

I was thinking of the Ista Mix Max with the impeller blade thing that breaks up gasses into smaller bubbles which is only $13. It's 12" long.

Effective diffusion is making the gas bubbles come into contact with as much water molecules as possible to prevent oversaturation of the water immediately surrounding the bubble. If the water is saturated, more gas can't be diffused so the size of the bubble stays the same. This is why bubbles caught in a current, like in a vortex, doesn't diffuse as efficiently as shaking it which causes a lot of turbulence, which forces non-saturated water into contact with the bubbles.

As for the issue of gas buildup, that's adding too much gas in less time than the reactor can diffuse efficiently. If the diffusion were more efficient, gas buildup wouldn't be an issue.

It seems like you designed the reactor to work around the poor efficiency instead of increasing the efficiency of diffusion. That's why it's ginormously large and bulky. If you focused on increasing the efficiency of diffusion, you'd be able to have something much smaller. 20" is HUGE!
 

mike

Guru Class Expert
Jan 13, 2012
169
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16
Quebec, Canada
I used to use the Sera 1000 in a 33G tank. It’s the same principle as the Mix Max large. It was not able maintain a stable CO2 around 30 to 40 ppm. I now have a 125G tank and I can’t imagine the Sera 1000, or the Mix Max could supply enough CO2. In any case, these units also create a vortex in the chamber. It’s really all about increasing the dwell time of the CO2 in the camber as water passes by it, so by having it go around the chamber it’s doing just that.

If the idea is to increase the contact frequency with water, why would a vortex, which moves water a greater distance in less space, not be effective? I think it’s the velocity of the water movement that is often the issue. I’m sure the bubbles in my reactor barely rise and are always traveling with the flow of the current, which in turn reduces the contact frequency of the water. In any case, your comments do give me an idea, rather than reduce the flow I will create a counter current in the opposite direction, which would also have a shaking effect on the water.

Mike
 
Mar 20, 2013
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Dissolution is about the interactions of molecules. The more violent the interaction the faster gasses dissolve.

I just did an experiment to test how long it would take to drop the pH of my tap water (pH=8.4 immediately out of the tap using API high range pH) down to under pH
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
Thank you for sharing your results with us.

I will be changing my internal design a bit. For starters I always knew my pump was too strong but I only wanted to change one parameter at a time to see what effect each change had. As it stands, the current design did significantly reduce the amount of co2 bubbles in the tank. There are two other changes I want to make; the first is to change the flow rate in order to allow the Co2 to remain in the reactor longer, and as a final change, I will move my 3/4 pipe and tee to the bottom of the reactor and have it angled up. This last change should create that violant shaking motion as the water and Co2 hits the top of the reactor and tries to make its way to the bottom to where the outlet is.

Mike
 
Mar 20, 2013
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If I knew more about physics at the atomic scale, I'd be better able to think of the best way to shear off saturated CO2 water around a CO2 bubble. That's the thing about dissolution, once the water becomes saturated around a bubble, it won't allow any more gas to dissolve. What is needed is a lot of force that will shear off saturated water and replace it with unsaturated water.

If we know how much force is required, then we can optimize a system that can simulate it and thus increase CO2 dissolution speed.

I was thinking about having two (or more) inlets into the chamber. Each inlet is directed at each other so that the force each stream strikes each other is twice the force, much like how a particle accelerator (aka: atom smasher) works.
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
I made some changes this past Sunday. I reduced the flow to about 400GPH from 900GPH and I lowered the Tee to the lower 3rd of the reactor and pointed the slots upward and I also added pot scrubbers to the bottom lower third, below the tee. I did this in the afternoon on Sunday, my lighting period was already half way done and I did it right after a water change. Yesterday, Monday, was the first day I ran it from start to end. When I got home, which is about 5.5 hours after the CO2 comes on, all the fish were at the top gasping for air and a couple looked lifeless. I quickly aerated with a power head and turned off the CO2. I try to keep my PH at about 6.3/6.2. With a KH of about 2.5 to 3, I figure I maintain about 45ppm of Co2. Yesterday the PH was 5.9. I have since dialed down my Co2 regulator quite a bit, I will have to find that sweet spot again. Luckily I didn’t lose any fish.

These changes again reduced the amount of CO2 mist in the tank and caused the CO2 levels to rise significantly. My goal is to remove all mist from the tank, so 100% dissolved co2 in the reactor. I’m going to let it run like this for 2 weeks while I try to find the sweet spot that will return my PH to about 6.2/6.3
 
Mar 20, 2013
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I'm wondering if instead of having the two jets swirl the water around upward, if you can just align the two jets exactly vertical. This might increase the impact pressure as the water hits the top of the tube and may increase the dissolution rate.
 

mike

Guru Class Expert
Jan 13, 2012
169
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16
Quebec, Canada
Yes it did have an effect. I have them pointing right up. There was again less visible bubbles in the tank and I had to again lower my co2 rate. I have to get my 20lb co2 tank filled this week, in the past a tank lasted me 7 to 8 weeks. I'm anxious to see how long it will last now, but that won't be till late October.

Thank you for your help.

Mike
 
Mar 20, 2013
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I'm glad I can help. I was looking at the inside jet outlets and was thinking that because the jets are cut and angled, much of the impact strikes the side of the reactor chamber and some water will inevitable move downward, not upward. Perhaps if you utilized two PVC elbow joints to angle the water flow it would improve the dissolution rate even more since more water will be forced upward into the reactor.
 

mike

Guru Class Expert
Jan 13, 2012
169
0
16
Quebec, Canada
That is actually what I did. I put an elbow at each end of the tee and pointed them straight up. I also lowered the pipe so the tee and elbows are about at the mid point of the reactor. Next time I open it I will take pictures.

Mike