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Dual Venturi Diy External Co2 Reactor

This co2 reactor costs about 20$ due to using Clear PVC housing, you can use solid 2" pipe if you wish.
  1. mcd19

    mcd19 Junior Poster

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    I'm sorry Tom but I am not familiar with the terminology you are using. I can't find a valve small enough to fit 3/16 tubing. Can you supply a link to an example of what you are referring to and a company that sells it. If I can see it, I will understand better. I am not going to set up the venturi loop, I just want to place a valve at the end of the 3/16 tubing so I can release any pressure buildup if needed. Thanks for your help.
     
  2. mcd19

    mcd19 Junior Poster

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    I think that I found something that will work. I will just attach a small pieace of co2 tubing to the rigid 3/16 tube and then attach this Aquatic Micro Ball Valves for Aquariums to the other end. Should work, I think.
     
  3. tedr108

    tedr108 Lifetime Charter Member
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    I recently built a DIY reactor and decided against putting the side venturi on it, just figured I'd use the top venturi. I made the 3/16" rigid tubing for the top venturi a little longer than in the original design so I could see it easily from the outside. I ran into a problem, however. Whenever I did a water change, it took a long time for the big PVC tube to fill completely, probably because the little Rio 800 pump just had too much air coming in thru the venturi tube. And, during this period, sometimes an hour or more, it was extremely noisy. Honestly, today I do not think it was going to completely fill at all ... it just kept running poorly for over an hour.

    My solution: I put a 3rd hole in the top and put a piece of very short 3/16" rigid tubing into it, so it just barely came thru the top cap on the inside. I then put a short piece of air tubing onto this, so it was long enough to reach into the tank. I do not have a valve to put on the end, so I simply folded the air tubing back over itself and rubber-banded it. Now when I start up my reactor after a water change, I open up the air tubing on the 3rd hole and the reactor fills almost immediately (when water shoots into my tank, I close up the air tubing) and runs quietly from then on.

    I still like using the top venturi method, so if I had to do it over again, I'd probably just put 3 holes in the top from the beginning.

    Perhaps I did a poor job building my reactor, but just wanted to share this, in case someone else runs into the same problem as I did.
     
  4. JHipkin

    JHipkin Junior Poster

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    How did this work out for you?

    I'm building a 120 gal tank and have the parts for an external reactor, which will be in the output line of a canister filter. I can loop the venturi line back into the cannister output / reactor input line w/ a "T" connector or have it feed a power head inside the tank. The advantage of the first plan is less stuff in the tank while the advantage of the second plan is more flow in the tank. I would like to hear your POV.
     
  5. Tom Barr

    Tom Barr Founder
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    Another idea is to use this powerhead with a needle wheel:

    Octopus Water Pumps - AquaCave

    30$ and it'll fry any bubble into mist.
    225gph.

    You can feed CO2 directly into the powerhead and place it inside the tank.
    Or add it a sump and feed the output to sump return pump.
    There are likely other applications.



    Regards,
    Tom Barr
     
  6. VaughnH

    VaughnH Lifetime Charter Member
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    I have the vent valve line at the top of my external reactor connected to a powerhead in the tank, with a drilled rotor, so I get CO2 mist as well as CO2 dissolved in the water in the reactor. This isn't working well.

    The problem is that the CO2 in the reactor doesn't remain there long enough for much of it to dissolve into the water, and CO2 mist is less efficient as a way of dissolving CO2, so I need to use considerably more bubbles per second to get acceptable CO2 level in the tank.

    The solution will be to follow Tom's original design more closely, and take the excess CO2 from the reactor at a point lower than the top of the reactor, so a CO2 bubble stays in the reactor at the top, with the incoming water flowing through it. I haven't done this yet, since it requires carefully removing the reactor so as not to dump a lot of water on the floor, drilling the hole, and reinstalling the reactor. Soon I will try this.

    A secondary problem was that I neglected to renew the solution in the drop checker for too long. That made the drop checker color be green when it shouldn't have been. It seems that the liquid needs to be replaced at least every two weeks. I'm not sure why, but the color is from a dye and dyes are notorious for gradually fading or otherwise changing color after prolonged exposure to light. Anyway, the result of this was me thinking I had good CO2 (green drop checker) when I didn't, thus masking the deficiency of my bleed valve method for connecting the "needle wheel" powerhead.
     
  7. Mooner

    Mooner Lifetime Charter Member
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    Reactor lockup

    Occasionally, enough C02 accumulates at the top of the reactor to stop the flow. Currently using the Dual venturi DIY External CO2 reactor show in this thread. Also using the 2 inch from the top hole looped back to the Rio 600. Running 3-4bps on tank w/sump. Everything is sealed and DC is green 2 hours after lights on. Would using the second (3") tube at the top of the reactor change and/or degas better? The current venturi is wide open, tried regulating with small drip valve but then it locked up daily. Any thoughts?
     
  8. Mooner

    Mooner Lifetime Charter Member
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    Reactor lockup

    Moved venturi to top hole next to CO2 in. WOW, I thought the misting was pretty good from the side hole, now the misting is 2, 3, maybe 4x better! unless it's because there is a fair amount of gas in the reactor right now. Will see tomorrow, might have to turn needle down a bit.
     
  9. Tom Barr

    Tom Barr Founder
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    You might simply need more than a Rio 600, try a Rio 800-1000 etc, or a maxi jet 1200 etc(not as bulky).

    Regards,
    tom Barr
     
  10. Mooner

    Mooner Lifetime Charter Member
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    Reactor lockup

    Well using the top hole didn't work either. In fact, only made it four hours before gas lock.:confused:

    Will try larger pump, this is on a 30 gal. Might blow fish away. The Rio 600 when working had good current/flow.

    Will let you know, thanks Tom.
     
  11. Tom Barr

    Tom Barr Founder
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    Might just try the needle wheel method and use that.
    Simple and will not lock.

    Regards,
    Tom Barr
     
  12. Mooner

    Mooner Lifetime Charter Member
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    Reactor lockup

    Well, not quite ready to give up:(

    Just got home to a locked up reactor. So i start fiddling with things to see what I can do. Now when I say locked, it means that there is about 2" of gas in the top of the reactor, a definite water level with no churning. Normal or initial operation is dozens of bubbles in what looks like a blender(see first pic), mixing in the reactor. This in turn sends hundreds of tiny(micro) bubbles out of the reactor and in to the tank. At some point during the day the gas builds up(with the venturi loop in either position fully open)and stops 95% of the flow out of the reactor.

    First thing I tried was to pinch off the factory loop from the powerhead output to the powerhead intake. Thinking that this was simply circulating air once the lock occurred. I noticed a very slight difference in operation, the venturi started sucking more water/less air. Flow was still down 90%. Then watching a lot of air moving through the venturi loop, I closed the valve on the venturi loop. Lock instantly broke and reactor returned to normal operation(see first pic) This is what is normal in the first part of the day. Also many micro bubbles entering the tank via the reactor(see second pic)
    Will watch and see if this will last daily/weekly without a lockup.

    Chris

    DSC02001.gif

    DSC02002.gif
     
  13. tedr108

    tedr108 Lifetime Charter Member
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    Chris,

    FWIW...

    I think Tom was right when he said you might need a Rio 800 or 1000. They make a Rio RVT 800 with venturi loops already built in (maybe your 600 has them too), which is what I used for my external reactor. I think they are available for under $20. There are non-RVT 800s, but it would be easier to use an RVT.

    Honestly, even the 800 was a little underpowered in my case, because occasionally my reactor wouldn't fill completely upon startup if the reactor had been partially drained by a water change. Then mine would go into the same state as yours, but that was at startup. I ended up having to put a bleeder valve in the top to be used at startup (after a water change only) just to get the reactor filled and going quickly.
     
  14. Tom Barr

    Tom Barr Founder
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    I see an overflow on this tank as well, this might be the source of the off gassing and why you need more flow etc.

    Regards,
    Tom Barr
     
  15. Mooner

    Mooner Lifetime Charter Member
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    Thanks Tom and Ted for the reply.

    I will get a Roi 800 with venturi and have it on standby. Will get back on how the 600 performs.

    Chris
     
  16. Mooner

    Mooner Lifetime Charter Member
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    Yes, that is a CPR overflow into custom sump(your design) Works very well. Overflow sealed with clear duct tape and sump sealed with window/door weather stripping.
     
  17. Grafalski

    Grafalski Prolific Poster

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    I've just build Tom's external reactor. I haven't use a powerhead. I hooked up my unit to eheim canister filter and I don't see mist coming out of the outlet line in my tank. When the CO is on I can see a dramatic drop of PH in the water. It looks that everything is working perfectly - no leaks, nothing. Here comes the question: Do I have to see mist coming out of it or this unit is so efficient that almost 100% of Co2 is being dissolved in the water?
     
  18. Mooner

    Mooner Lifetime Charter Member
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    Do you use a drop checker? Or do you see plants pearling?
     
  19. tedr108

    tedr108 Lifetime Charter Member
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    Grafalski,

    I didn't see misting from mine until the afternoon sometime. When there is no misting, the CO2 is completely dissolving as you surmised -- that's a good thing! :) If you never see misting in the afternoons, you may not be getting enough CO2. A drop checker is the only sure way to know if you are getting close to the 30ppm that is normally recommended.
     
  20. Grafalski

    Grafalski Prolific Poster

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    It's a new setup - no plants, no fish. I have a a drop checker that shows yellow color when the CO2 bubble rate is high.
     
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