Diffusing CO2 Into a Large Aquarium

[Avalon]

Actually, you could use this method for any aquarium, but it would probably be more worthwhile on a larger aquarium, say 55g and up. It's very simple, and very cheap.

You will need a powerhead with a venturi (a cannister filter would be ok too), some pvc pipe or some rubber tubing (clear is preferred) w/ an endcap, 3 or 4 clippy things with suction cups, a drill, and some CO2.

The pipe or tube will essentially become a spraybar, which will be placed at the bottom rear of the aquarium. Drill some small holes along the length of it, cap it, and hook it up to the powerhead, stick the CO2 line onto the venturi inlet on the powerhead, and BAM--even CO2 distribution with mist!

Here is why this method is superior to most others:

1. There will be no gaudy equipment stinking up the aquaium because everything will be out of sight (if you plant correctly).
2. The powerhead will chop up the CO2 bubbles creating a mist effect, which will rise up through the plants throughout the entire length of the tank. Misting is ideal because CO2 will come into direct physical contact with the plants. More CO2 = better growth.
3. It's cheap. Aside from a powerhead of your choice, this only cost me $3.46.
4. Flexible tubing can be run underneath the substrate if your 'scape so requires it.
5. Better plant growth = less algae.

Pics!

This pic shows the simple connection to the powerhead, a Rio 600, with the CO2 line connected to the venturi. My oto likes it...


This pic shows the endcap (it was free). I've since straigtened out the line. When I replanted, you can't see any of the spraybar or equipment.


Additional Notes:

The Rio 600 (200 gph) seems to be adequate for a 75g, but one size larger should work too. You can adjust pressure by drilling more or larger holes in the tubing, or larger/smaller gauge tubing. I am using .75" tubing (OD) with 10 holes. I would use the RIO 600 for a 55g tank, and possibly one size smaller tubing.

[zoo minsi]

wow kewl idea avalon, i may have to give that a try when my regulator comes in.

[phOOey]

kinda digging up an old thread, but this idea got me interested, and i think im gonna give it a go, i've already got all the stuff i need, i just need to set-up a way of producing c02.

anyways avalon, how many holes would you say is best in the pvc, i mean how large should they be and what should the distance be between each of them?

[Avalon]

Originally Posted by phOOey

kinda digging up an old thread, but this idea got me interested, and i think im gonna give it a go, i've already got all the stuff i need, i just need to set-up a way of producing c02.

anyways avalon, how many holes would you say is best in the pvc, i mean how large should they be and what should the distance be between each of them?

The amount of holes will depend on a few things, such as the flow rate on your powerhead and size of holes, as well as how much pressure you want. You can use a #40 drill bit, or something close to the size of the holes on any spraybar. As for how many holes, that will be something you may have to experiement with. Be sure not to drill too many holes at first. It's easier to drill more later! I would say try to keep the distances between them equal.

[Orion]

Very cool idea Avalon. Any thoughts as how this compares with other types of CO2 diffusion methods?

I would think that using PVC would be better than the soft tubing because that would allow for an easier time getting the same sized holes though out the pipe.

Also how would it affect the amount of CO2 getting in the water if you placed the holes along the bottom of the pipe facing down? This would ensure that very little gas would escape into the water, giving more time for the water to become saturated with it. I don't know, because if too much gas began to collect and the bubbles become to large then the water isn't going to be able to absorb it as well.

[Avalon]

Originally Posted by Orion

Very cool idea Avalon. Any thoughts as how this compares with other types of CO2 diffusion methods?

This idea uses the "mist" approach that essentially says that physical contact of CO2 with plants = better plant growth. And it does. I would say it's one of the better methods. I recently outdid myself and created my own "Fogger™" method. It uses a strong powerhead and it's own pre-diffusion device. The result is a massive fog of CO2 that circulates throughout the tank using direct reflection technology (DRT™) for bidirectional flow (BDF™); collectively known as unidirectional reflection technology (UDRF™). Forget the mist! Yes, I am full of it today!

I would think that using PVC would be better than the soft tubing because that would allow for an easier time getting the same sized holes though out the pipe.

Well, PVC, or acrylic (better choice), I think would be better, but not for that reason. Keeping the pipe even is key when dealing with the buoyancy of CO2 gas. It would eliminate collection spots in the hose. However, you could combat this in a flixible hose with more water flow (pressure).

Also how would it affect the amount of CO2 getting in the water if you placed the holes along the bottom of the pipe facing down? This would ensure that very little gas would escape into the water, giving more time for the water to become saturated with it. I don't know, because if too much gas began to collect and the bubbles become to large then the water isn't going to be able to absorb it as well.

The point of the mist idea is to have bubbles in addition to the saturation point of CO2 in the water. Direct contact of CO2 with the plants is the goal. Anyone that uses CO2, without a reactor, has already experienced this. They just haven't realized it. Case in point, 100% saturation of CO2 in the water is not enough.

[Orion]

I can dig it. Very interesting yet.


Is that a tad bit of "BS™" in that post as well?

[Avalon]

Originally Posted by Orion

Is that a tad bit of "BS™" in that post as well?

Yes and no. The rhetoric, yes, the science, no. But yeah, there's a bit if stinky I tracked in as well.

[fishtrap]

Diggin up yet another oldie...
Avalon, I would guess that your splitting your Co2 feed from a single source (unless your a complete geek and have two Co2 bottles under your tank). One to the reactor and one to your mister. How are you doing this? Are you using individual needle valves for each unit?

[Avalon]

Yes, I'm actually splitting the single source 3 ways: 2 for the 75g, and one for a 10g. I'm using some (2) Y-valves I picked up at a local welding supply shop. They have needle valves for each output, but aren't as accurate as I'd like. It takes a long time to get them set right. Adjust one, and it changes the pressure on the others (I think this is a problem with all "gang" valves). I've finally got it dialed in right. I use the regulator pressure valve for "global" modifications. It's kind of ghetto, but it works. Currently, it's working really well.

As an update to the thread, I've found that the spraybar approach lacks when used behind a dense background. If there is some break-up in the background planting, then it should be fine. Also, I think in long tanks (>48"), this method would be ideal.

I currently diffuse CO2 into my Eheim 2028 cannister and into a strong powerhead for the mist effect and extra circulation.