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Discussion Starter · #1 ·
I have built this style reactor and I can't stop the top from filling up with CO2. I am using the recommended Rio 600 and I have tried several others with the same results. Even with the bubble count turned down to 1 per 3 seconds they just don't dissolve fast enough. Any thoughts? I am thinking of just buying the Ehiem diffuser.
 

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The reactor that i got delivers the water to the top while the co2 input is at the bottom. In the reactor's bottom is filled with a layer of ceramic rings to delay the CO2 from reaching the top. when the Co2 reach the top, the water turbulence causes a vortex like action which helps to further dissolve the CO2 into water. Hope it helps.

Vincent
 

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I think the bioballs would help a bit. I think HeyPK told me that as the co2 goes out of the bubble O and N go in it. So you may still have pretty good absorption.

I have a nipple at the top of my reactor with a piece of airline tubing terminated by an air valve. I open the air valve every couple of days to bleed out the gas.

What is important is your CO2 ppm readings. Are you getting 20 ppm CO2? If so, you don't have a problem.

The Eheim diffuser works well up to 75 gallons.

Steve Pituch
 

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Discussion Starter · #5 ·
From the size of the bubbles I am not sure it is not air instead of CO2 but I can't figure our how air is getting in as everything is under water. It is a new tank and maybe some of the new tank bubbles are the problem. As far as making a vortex the unit basically is a modified gravel cleaner and the inlet is in the center. If you have any pics of your ideas please pass them along. Thanks
 

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What you are seeing is completely normal, it simply means you don't have enough pressure to push undissolved gasses out of the tube. I made the same reactor and battled with undissolved gasses for some time. The trick is to simply remove any restriction from the bottom of the tube. Once you remove everything from the tube, adjust the water flow so that only the real tiny bubbles get pushed out of the reactor. Works like a charm and unless you have too much flow, which you don't if you are having this problem, there is no need for bio-balls or other restrictions in the tube. They are there only to slow down the bubbles in order to keep them from being pushed out of the reactor too quickly.

You can kind of see how mine works in this picture:


You also want to make sure that you left no lip around the hole where the water enters the tube (the inside of the blue cap), any gas that reaches the top of the tube should be able to flow to the center and intersect the water flow again. I did this on a lathe but you can sand it away quite easily or cut it with a blade.

What you also might want to do is place the reactor on a timer and set intrvals where the reactor turns on and off 2-3 times a day, this outgasses the any remaining undissolved gasses and also pushes away any floating debris that has collected around the pump intake.

Hope that helps
Giancarlo Podio
 

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Discussion Starter · #7 ·
gpodio said:
What you are seeing is completely normal, it simply means you don't have enough pressure to push undissolved gasses out of the tube. Hope that helps
Giancarlo Podio
Thanks very much Giancarlo, and the picture. Do you turnoff the pump at night too?
 

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Discussion Starter · #8 ·
I got it worked out and it is working awesome right now. Giancarlo your pictures started me thinking about a 90º elbow I was using. The pump needs to be a straight shot into the reactor plastic. I had a 90º elbow to take advantage of the suction cups. I went to a straight in and used plastic cable tie to secure the suction cups. No the flow is sufficient to remove any trapped air inside yet churn the CO2. Any bubbles that escape the bottom are now so small that they completely dissolve long before reaching the surface. Thanks again.
 

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You can also try feeding the CO2 into the intake of the powerhead rather than into the reactor chamber. When you try this, make sure the intake is facing the water surface but well below it to prevent possible airlock problems. The impeller grinds the CO2 up pretty good and efficiency is greatly increased.
 

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I tried this once but I think I would need a stronger powerhead. With the prefilter in place the pump didn't have enough power to pull the bubble down, without the prefilter I started to have problems of plant tissue getting pulled into the impeller and reducing flow. If only this little pump had a venturi like the Duetto filters, that would work very nicely. But can't complain, it's been working for a year now, just needs some cleaning as I've been neglecting things lately.

Giancarlo Podio
 
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