# Co2 Reactor Question!



## krissy (Jun 3, 2014)

I just made a DIY co2 reaction. Simple clear PVC tube with co2 line on the bottom and the water flowing from top to bottom.

Basically co2 bubble flows from the bottom to the top and the water enters through the top and exits the bottom of reactor and goes to the outflow.........

I am using an ehiem 2217 and the flow seems too strong for the co2 bubble to flow to the top for the water to chop up... the co2 bubble goes straight through the bottom and to the outflow.

Any suggestions that i could try to fix this? I tried lowering the FLOW by slightly closing the on/off connector of the tubing on the eheim and it worked. But wouldnt restricting the flow harm my filter?


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## Cavan Allen (Jul 22, 2004)

Anything in the tube? Bioballs?


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## rjordan393 (Nov 23, 2012)

The CO2 injection is supposed to enter near the top of the reactor along with the entering water. 
Is it possible for you to turn the reactor so that the bottom is now the top?
If you used threaded fittings on one or both ends of the reactor, then you can try filling it with either bio-balls, bio-stars etc depending on the diameter of the reactor. This is a very effective means of dissolving the bubbles, providing you can place the CO2 tubing near the top.
What size is your tank and what is the diameter and length of the reactor?


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## krissy (Jun 3, 2014)

Nothing in tube. I heard itll clog if i put anytjing in it. I can turn the tube upsides down and the co2 will be on top. But my question is, if i open my flow all the way on 2217, it will quickly fill the whole pvc with water thus eliminating any type of water splashing thats suppose to mix the co2... ill just have big co2 bubbles traveling out the outflow. 

I have my eheim tap connector half way closed to reduce the strong flow and the reactor is working. I can see the bubble flow to the top 1by1 and water splasing mixes and it exits....

Will this hurt my filter? Is there a better way to do this???


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## rjordan393 (Nov 23, 2012)

If your thinking about mulm attaching to the media; that may be possible. I have bio-balls in my 3 inch inside diameter CO2 reactor and it is experimental to see if the media does collect mulm. Then I'll decide whether to let it be or remove them. I made my reactor 4 feet long. The first reactor I made was 2 inches inside diameter by 4 feet and it was not large enough to handle bio-balls and I was getting CO2 bubbles out of the discharge. I see by the specifications that your Eheim can handle a 160 gallon tank. You have not stated the size of your aquarium or the inside diameter and length of the CO2 reactor.
So at this point, your canister's flow is either to much for your tank or you need to build a bigger diameter reactor.
I have a Marineland model 350 magnum feeding my 3 inch diameter reactor. But I assume the 350 means the gph at zero head. But in reality, I think I am getting between 200 to 240 gph after the water leaves the reactor to be discharged into my 75 gallon tank.
Your reactor should not have air in it. You need to place a tee fitting at the top and fill the reactor slowly to bleed the air off. Then seal the opening with a npt plug using Teflon tape.

Slowing the water flow will not harm the filter. However there might be guides available giving the minimum and maximum flows for tank size. So use them as a guide. They are not written in stone.


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## krissy (Jun 3, 2014)

I am using this reactor on a 48 gallon. It is a schedule 40, 1 inch diameter, clear PVC pipe.

I found out the problem. The 2217 is too strong. I was doing some research and read that adjusting the double tap valve on the OUTPUT side of the eheim will NOT harm the motor since it is magnetic. When i turned the flow down a little via the valve, the reactor now works perfect!

Its a 1 inch diameter by 12 inch long. I have it set vertical and the co2 bubble is coming from the bottom. After adjusting the valve to slow down the flow a little, I now see the bubbles flow to the top where the water is coming in and it mixes, then exits through the bottom and out the OUTFLOW.

THANKS GUYS!!!!!!!!!!!!

=)


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## krissy (Jun 3, 2014)

I hope this is better than my previous setup which was with a glass diffuser and a mini power head above it. I would get pearling within 1-2 hours.

Since with this reactor, I will not see bubbles, will the plants still pearl??? My lights are still off so I cant judge yet.

:0P


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## rjordan393 (Nov 23, 2012)

There's no reason why it should not. When injecting CO2, and you see no bubbles coming out of the discharge, then you know the CO2 is fully dissolved.


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## rballi (Sep 6, 2009)

Put the reactor at a 20% angle. That helps to dissolve the gas without limiting flow.


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## Tugg (Jul 28, 2013)

Honestly, I would just start over. A 1 inch diameter reactor isn't much of an increase in diameter. This means the water doesn't slowdown and just grabs the bubble and pushes it out. Using a valve to decrease the flow of the pump is just artificial head pressure. It may get the CO2 dissolved, but at the cost of total flow and filtration.

Normally on a Rex Grigg style reactor (vertical PVC tube using counterflow), you're looking for 2-3 inches. Preferably, having it about as tall as the stand will permit. The point of the increased diameter is that it slows the water down and gives the bubble a chance to try and fight the current. Once it exits the reactor, it returns to the normal diameter and the flow increases back to about what it was. This produces very little head pressure, and allows the pump to run at it's full capacity.

If you put some very course material, such as a little bio bale, or the larger bioballs, there really isn't much chance for it to clog. The filter would have already collected any large debris, so it's only bacterial growth/mulm that will collect. This is a fine dust/sludge that will thinly coat the insides and give it that common brown color, but it would take ages for it to accumulate to a level that would impact the flow. This provides some increased turbulence to help chop up the bubble and get it dissolved.

Our planted tanks usually run more on the acidic side, we don't get the hard mineral depositing/scaling that you can often see accumulate in saltwater plumbing. Even if you have super hard water, you're injecting CO2. It would dissolve any mineral deposits inside the chamber anyway. That's the underlying principle in how a reef tank's calcium reactor works.

There isn't much point to injecting CO2 if you don't have good flow in the tank to spread it around and feed the plants.

Also, you shouldn't have any air in the reactor. That means either CO2 is not getting dissolved fully and is accumulating, or that you didn't purge it and it has a bunch of nitrogen and oxygen trapped. You can back siphon it to clear this out when you first set it up. Just close/disconnect the doubletap between the reactor and canister. Then in a bucket, open the reactor side's doubletap valve. This will cause it to flow backwards, sucking the air and water from the top of the reactor out. Once it's clear of air, close the valve and hook it back up.


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## abrooks12376 (Jul 22, 2014)

Here's one I made, $35-40 all in, clamps and compressing fittings make this bad boy 100% leak free.. I've since changed the angle to around 20% as mentioned above, seems to be the sweet spot. I run a cannister rated for 350 gph, 6 bps with 100% saturation, no bubbles whatsoever. I'd highly recommend this style.. about 25 bioballs inside, it does make some noise occasionally. I wanted the balls to be able to bang around in hopes of A- chopping bubbles and B- keeping bio build up minimal.


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## krissy (Jun 3, 2014)

Thanks everyone for replying.

I think tugg is right that my diameter of reactor is too slim causing the co2.bubbles to flow right out instead of flowing to the top where the water is coming in...

I'll trying making a new one also with bio balls

Thanks everyone!


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## krissy (Jun 3, 2014)

Tugg heres the example of exactly how i plan on building my cerges reactor.

No sponges or anything inside the housing.


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## krissy (Jun 3, 2014)

IM planning to use a clear housing so that i can see inside.

The water should go into the housing and travel down then UP the WHITE tube and out to my tank. Is this right??

Will a reactor like this basically allow me to turn the flow all the way up on my eheim 2217


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