here's my DIY CO2 reactor/diffusor

[mistergreen]

I just installed it in my tank. Let me know what you think. Would it work?



the tube is full of holes so fresh water can exchange with the co2.
The tube is placed near a filter intake tube.

oh, the idea is the little co2 bubbles get caught in the sponge where it's given time to diffuse into the water.

[sandiegoryu]

that is very clever i dea, but I recommend putting it near the filter outtake rather than the filter intake. And I think a diffuser works perfectly fine alone, as long it is good enough.

[epicfish]

I'm assuming you mean filter intake tube? If it's a HOB filter, I'd just get a sweetwater diffuser and put it under the intake. Or just plumb the CO2 directly into the intake.

If you're using a caniser, why not use an in-line reactor?


But to answer your question, yes it'd work. However, as more and more bubbles get trapped by the sponge, they're either going to form a large bubble and quickly escape to the surface, or they'll just form a CO2 pocket in the 1" diameter tubing with very little surface area for gas exchange.

[mistergreen]

i have a DIY CO2 yeast sugar thing.

i just took a look at this in action. some little bubbles are getting trapped in the sponge but most are getting caught in a pool of co2.. It builds enough bouyance and shoot straight out of the tube. I'll have to fudge with the level of the sponge and how compact they are.

All this time I've been sticking the co2 line straight into the intake of the external power filter... It doesn't add too much co2 into the water column.

I'll move it away from the intake tube. thanks.


i'll try to find a bigger tube like a siphon tube but it's like $12!
I tried the hardware store but couldn't find any...

btw.. this cost me $5 to make

[dufus]

maybe close the top of the tube and poke tiny hole in it so tiny bubbles happen?

[mistergreen]

it works.. it raised my KH up 1 degree... but I still need it to be more efficient.

here's version 2.



this should work better.. it's made out of a plastic container and sponge media.. I think the sponge works great. The surface area on a sponge is huge because of all the holes in it.

[spypet]

I think this design idea is flawed for 2 reasons.

-the bubbles will simply join into a large Co2 pocket under the sponge, and not diffuse at all, or possibly leak down under your substrate.

-whatever Co2 makes it up through the sponge will coalesce into large bubbles and poorly diffuse as they quickly rise to the waterline.

[mistergreen]

yup, he co2 pools because all the bubbles are going to the same spot... however the CO2 is in contact with H2O for a long time and is given the chance to dissolve without rising to the waterline.... I'll give some data later..
before this the CO2 concentration is 9ppm.
will test in a few days.

[dufus]

could you make a fully inclosed tube with 2 holes? 1 to pump co2 into the tank, the other to let water in/co2 out? or put a small hole @ the top of the tube to let c02 out.

[mistergreen]

sounds reasonable... the reason for it being not closed is that the more surface area CO2 has in contact with flowing water, the better rate of gas exchange. If it's just a little hole, then not much gas is exchanged and it just sits there.

oh, i modified it a bit.. the foam is now a dome instead of being flat. the gas collects in the center instead of going out the sides.

[Storm_Rider]

aren't you supposed to discourage the co2 from collecting into a pool? i ask sincerely because i don't know what's going on haha

[dufus]

Originally Posted by mistergreen

sounds reasonable... the reason for it being not closed is that the more surface area CO2 has in contact with flowing water, the better rate of gas exchange. If it's just a little hole, then not much gas is exchanged and it just sits there.

oh, i modified it a bit.. the foam is now a dome instead of being flat. the gas collects in the center instead of going out the sides.

I was thinking about the water coming in from beneath, therefore contacting/exchanging CO2, then leaving, the hole in top would be to vent the excess gas out.

[essabee]

Why not take a air tight plastic jar, make some holes in the bottom, cover the floor with a foam pad, introduce the CO2 from the top, and if possible also pump water in from the top. I think that would work.