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Thread: CO2 rector with just a power head and lots of airline

  1. #1
    Join Date
    May 2009
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    CO2 rector with just a power head and lots of airline

    Hello everybody,

    I think I found an inexpensive (as in really cheap) way to dissolve CO2 in a tank. It's so simple, it's probably been done before and the old timers in here will probably point out that they were doing it this way years ago. It's kind of a mix between a venturi and a good old ladder.

    With time, I came to realize that CO2 is easy to dissolve in water. If the gas remains in contact with flowing water for long enough, it will dissolve.

    All you need is the following:

    1. A powerhead (with venturi input)
    2. A standard T
    3. Lots of airline (I'm testing it with just 6 feet, it's what I have laying around... more could be better)
    4. A small piece of foam/sponge (like the sponge inserts in filters)

    Here's a crappy plan, I have not included the checkvalves:



    Some CO2 still makes it to the powerhead, but compared with the gas that is sent in the system, it's not that much. I think that if I use 10-15 feet of hose between the powerhead and the T connector, more gas could get dissolved, not certain yet...

    Any thoughts?

    Cheers!
    Last edited by argnom; 05-04-2010 at 10:58 PM.

  2. #2
    Join Date
    Jun 2009
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    Surprise, AZ
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    A Snort of CO2

    Hi,

    Generally, replacing the “airline” (tubing) with a vessel or “reactor” will provide a similar outcome.

    Replacing the tee with an eductor, even just one meant for filling waterbeds will improve the efficiency

    Placing the output of the eductor to the input of the powerhead or pump will improve the pressure differential.

    Biollante
    Last edited by Biollante; 05-04-2010 at 11:13 PM. Reason: Left a sentence out
    The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

    Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.

    • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
    • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
    • When in doubt "don't."

  3. #3
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    May 2009
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    Quote Originally Posted by Biollante View Post

    Generally, replacing the “airline” (tubing) with a vessel or “reactor” will provide a similar outcome.
    Indeed, but I'm really rubbish at making and watertight vessel... I tried to make an external reactor like the ones Redsea sells.... The reactor worked really well, but there were leaks. I really do not trust my craftsmanship when it comes to water. I'm certain that my landlord downstairs will appreciate it.

    Quote Originally Posted by Biollante View Post

    Replacing the tee with an eductor, even just one meant for filling waterbeds will improve the efficiency
    Probably, you really like those eductors Biollante don't you. The thing is, I read that they are rather noisy and I like my tank to be silent. The bonus is that since the "leftover" gas does not pass through the imperller, I don't get the chopping noise. Are eductors really as noisy as some people claim?

    It's only been 24 hours since I set it up and as of now, the CO2 levels look really good. I may even adhere to the "church of use a solenoid". Oh yeah and that ugly Hagen ladder will be history.

    I'll try to add a longer airline and an eductor sometime this week to see what happens.

    Thanks for the comments Biolante.

  4. #4
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    3,210

    Wink Hanging Out At APC?

    Hi,

    I have never found eductors to be excessively noisy, I just went around listening to a few, I confess I use the high end ones these days but like pumps and other devices there may be some tweaking necessary.

    In fact, I never recall any eductor noise complaints; I have certainly had complaints about pumps, aerators, filters (especially canister filters), fish, all kinds of things, even lights.

    It is possible the noise is a plumbing side affect, anytime we are moving gas and liquid through pipes I guess there is an opportunity gurgling and hammering.

    Many folks use the Python water change things; I used a diy version for years, never recall any noise.

    If you check in the diy area Tom Barr has posted some nice ways to make reactors and such.

    Biollante
    The first sign we don't know what we are doing is an obsession with numbers. - Johann Wolfgang von Goethe

    Disclaimer: I am not trying to make you mad, it is just what I am, an evil plant monster, 'nuf said.

    • I believe the information I am giving is sound, I am not a veterinarian, professional chemist or particularly bright and certainly not a "Guru.".
    • I assume you are of legal age, competent and it is legal for you to acquire, possess and use any materials or perform any action in your in your jurisdiction.
    • When in doubt "don't."

  5. #5
    Join Date
    Jan 2009
    Location
    Washington, DC
    Posts
    1,081
    Hello argnom,

    I like your idea. It is simpler then an idea I have for a DIY project. For now I use a Duetto multi filter I modified to inject CO2, but there are some similarities. Instead of the intake filter being at the bottom of the tank it is closer to the surface. The idea is to bring in some oxygenated surface water down to the substrate along with the CO2 and instead of airline tubing it is a ridged plastic shaped like your airline tubing, with three folds, only more compact. http://www.barrreport.com/showthread.php?t=6231

    Ballante's idea of using an eductor sounds like it would improve the efficacy over a standard T. It's not the eductors themselves that are noisy.

  6. #6
    I can't recall much, if any, sounds with any eductor I have, or rather have not, heard. The python sometimes whistles a bit but I have to say I expect that's more a pipe issue and I've specifically restricted flow at that point - open it back up and there's not really any noise specific to the plastic bit. Any of the Penductor type devices I've seen have been pretty open. I have no idea how you'd get any noise from those. Any noise in the tank I saw with that in it was definitely the normal pump hum. You may have a point with the impeller buzzing as it chops the CO2 as it can be distracting but in all fairness with a solenoid on the unit it's a non issue when there's no CO2 flowing. A simple submerged powerhead flowing into a large open tube is a fairly easy reactor to assemble and it's all in the tank so your risk for leaks is pretty minimal if you want to try it.

    -
    S

  7. #7
    Join Date
    May 2009
    Location
    Montreal, Canada
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    Hi everybody,

    Thanks for all the posts.

    Eductors are not as noisy as I thought it seems. The one video that I saw that had decent sound (and not some boom boom music) was of a marine tank. I think the eductor was left to the open air and not connected to a CO2 cylinder. The sound I heard must have been from the outside air rushing in.


    Update on diffuser:

    I works. More or less. It's far from being perfect though... I was able to get maybe 75-80% dissolution of the gas, there seems to be a point where adding additional tubing does not help much. The gas just stops dissolving. Perhaps the water in the tubing becomes too saturated to readily dissolve more gas.

    Also, as one adds more tubing, one also need a more powerful powerhead/pump. If I add too much gas from the regulator, the powerhead and the long section of tubing become "air jammed". The gas just exits from the sponge where there is now less resistance (since the pumps no longer does it's job). You also have to prime the tubing. I don't mind an occasional swig of tank water, but I try to avoid it.

    The conclusion is that it can work. If someone wants to add CO2 on the cheap. It is by no means perfect and it will not dissolve 100% of the gas, but since a lot of us already have powerheads, tubing and a T laying around somewhere, it can do the job.

    I have finally opted for a DIY internal reactor based on Tom's plans except on mine, I made it so that the powerhead stays horizontal and so does it's output (I wanted to use the suction cups of the powerhead and to use it to create additional circulation). It works well, dissolution of the gas is not 100%, but gas is relatively cheap... The way I setup my DIY reactor also creates a misting effect, so that's a bonus right there.


    I think it will do nicely until I get my hands on an eductor. I could try to get one for free... Hummm...

    Biollante, send me an eductor asap or I'll send Godzilla over to your place. Now you remember what happened to you last time you two met right?

    / I know, it won't work... Biollante is not scared of the threaths uttered by a mere human
    // And I lost Godzilla's phone number...

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