Is my DIY C02 Functioning Properly?

M

mfpreach

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Feb 8, 2006
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Hello all,
Thanks for looking at my post. I'm fairly new to the aquarium world, and I am loving every minute of it!

Anyways, I built my own C02 injector and just have one question.
The reactor is working fine and so is the mixture. Currently I am just using tubing with a piece of chopstick wedged in the end (no ladder or commercial diffuser). The result are very tiny bubbles.

My question is, are those bubbles being absorbed into the water? They go to the surface and then are thrown against the glass, and sometimes just dissapear at the top. They get thrown towards the glass because I have placed the tubing under neath the AquaClear 300 filter (a considerable current).

I can see molecules in the water, and the water is a little bit more hazy than usual because of these molecules.

SO, is the c02 diffusing inside the water?
I have only had it running for about 2 hours and the ph has stayed pretty much the same, I don't have a kh kit here so I can't test that out.

Also, how many bubbles should I have going out, it spurts out pairs of tiny bubbles. Hope i'm coherant enough.

As and aside, i went to purchase the Ebo Jager bubble counter diffuser from drfostersmith.com and learned shipping to canada is $40 fed ex! That for a 1.19$ piece. If someone wants to buy one in the states and ship it to me that would be awesome.

see: http://www.drsfostersmith.com/Produ...ll&Ntx=mode+matchallpartial&Np=1&N=2004&Nty=1

Thanks.
 
Hrm, IME you really should not run CO2 unless you have a KH kit. You will have no way of knowing what your CO2 levels are and whether or not your tank will remain stable while you inject. Injecting with a KH of 3 or under is dangerous. If your KH drops to 0, you could lose your biofilter.

Suggest you pick up a KH kit ASAP. Also, although this is DIY CO2, you might want to post in the Plants Forum since your question is more related to diffusion rather than building.

Roan
 
THanks for the quick reply,
I had my KH tested today, and it was around 4, so I thought I was good to go.
ANywyas, the bubbles are filling the water (I put my hand in or a net, and they get covered with bubbles), I guess that is right?

Thanks.
 
I might have my terminology backward, but I think the reactor is where the CO2 produced by your DIY setup is diffused into the aquarium water by more vigorous means other than simple bubbles streaming into the free water column.

For a DIY setup, most often the CO2 production part of the whole system is called a fermenter (if that is what you're using to produce CO2, i.e., sugar and yeast).

Use this link for a good e.g. of a reactor:

Drs. F & S CO2 Reactor

Two hours of simple bubbling via an air hose should not change pH much at all, but then again, how big is your aquarium, and how big is your fermenter and how much sugar are your using? Also, your "pinch of yeast" may be bigger than mine, since a "pinch" is not a standard unit of measurement. ;)

The CO2 bubbles streaming into the outflow of your Hagen AquaClear will help diffuse CO2 more thoroughly into your aquarium water, but not nearly as well as the reactor pictured in the link. Two of the variables (not the only ones) to diffusing as much CO2 as possible into the water are turbulence and holdup time, that is, in oversimplified terms, how vigorous the mixing of CO2 and water is along with how long this is allowed to occur. In your setup, the mixing is fairly vigorous, but the time allowed for this is fairly short.

Is your setup producing a spurt of bubbles every few seconds? Bubbles aren't a great unit of measure either, but it's all we've got when it comes to counting CO2 output and seeing when our fermentation setup is starting to wither to a stop. My small tank fermenter spits out a couple small bubbles every 5-6 seconds, and my big tank fermenter lobs a stream of a dozen good-sized bubbles every 25 seconds. For me and my kH, this low output is enough to avoid crazy pH swings.

In answer to your question, CO2 is diffusing into your water. Two ways I could tell it was working in my tanks: (1.) the plants got greener, and for the first time ever I had to start pruning them, and (2.) pH dropped a bit over the course of a week from 7.2-ish to 6.8 to 6.9. BTW, pruning has a side benefit...plants use nitrates when they flourish, and removing greenery by pruning is akin to removing nitrates.

For a quasi-reactor, instead of buying that diffuser, why not position your CO2 outlet hose so that the opening is right next to the inflow tube of your AquaClear filter? Any bubbles will be sucked up, pulled up through the inlet tube and given a thorough thrashing by the impeller, and then pushed thorugh the media, all this increasing holdup time and allowing more CO2 diffusion prior to the water being redeposited back into your tank. On the minus side, that sheet of water streaming over the AquaClear "spillway" might cause some CO2 to diffuse back into the atmosphere.

That's enough for one reply. I'm a complete newbie at CO2 fertilization as well. YMMV.

v/r, N-A
 
Positioning the tube under the aquaclear intake sounds like a great idea, I will try that.

It is creating many small bubbles in 1 second spurts, maybe that is too much?
I haven't noticed a drop in ph yet, but i'm sure I will tomorrow.

I will take off the chop stick and stick it under the intake.

If anyone knows any other good ways to diffuse the bubbles efficiently, other than purchasing a ladder, please let me know!

Oh, and its a 30 Gal tank with Hygrophila, Java Fern, Moneywort and an Amazon sword. Also about 15 fish.
Thanks.
 
FWIW, my wife's tank (I do all of the tank husbandry) is a 38gallon w/ swords, hygrophila and egeria densa, all easy-to-grow stuff. Our tanks are pretty similar in size and flora make-up. Her tank has a betta, guppies, platies, and SAE's (siamese algae eaters). About a dozen fish, total.

The DIY CO2 on that tank is a 20-oz pop bottle w/ a 1/2-cup of sugar and some yeast. Right now, w/ a day-old mix in the fermenter, it burps out a couple bubbles every 30 seconds...this will pick up in a couple days to around one burp every 5-6 seconds as the mix ages a little.

Just use your pH test kit to keep an eye on it. Your KH of 4 is lower than mine (5-6), so I'd think your pH would swing a little quicker than mine did, but mine required a week to make the change. One thing to remember (from high school chemistry) is that numeric changes in pH are logarithmic. A shift from 7.2 to 6.8 is actually a pretty large swing, even though the raw number shifts aren't that big. It's still well within the range that my particular list of fish will tolerate. Again, your mileage will vary.

v/r, N-A

P.S. I'm still agog over Drs. F & S charging $40.00 to FedEx that little diffuser. If they can get away with rates like that...hmm, maybe that should be my next employer!
 
You should be able to detect a drop in pH within a couple hours. CO2 is always diffusing out of the water into the air and if it's taking so long to detect a change, you've lost too much (or didn't have it in the first place). That is, the rate of off-gassing is = to dissolution which = no change in pH.

If you can swing a small water pump, check out this in-tank reactor... http://community.webshots.com/photo/66733948/1209978429045182475RguQNZ

It's a bottle with the bottom cut out. The pump pushes water down through the bottle while the CO2 is trapped inside. Worked well on my 90gal. There's a few bio-balls inside to help create turbulance but other media could work.

HTH
 
The bubbles are going into the aquaclear but I don't detect a change in ph.
It seems to stay around 7.5/7.6
For a 4 litre container i used 4 cups of sugar, 1 tsp of yeast, 1 tsp of baking soda, 1 tsp of protein powder, and lukewarm water. I shook it up and it is putting bubbles out.

The bubbles 1 per 2 seconds is going into the aquaclear intake and being crushed in the filter.

What could be wrong?

Should I turn down the aquaclear? (Turn the power to the right)

Also, I see tiny particles/bubbles floating around, isn't that visual evidence its working?

Thanks.
 
Last edited:
mfpreach said:
The bubbles are going into the aquaclear but I don't detect a change in ph.
It seems to stay around 7.5/7.6
For a 4 litre container i used 4 cups of sugar, 1 tsp of yeast, 1 tsp of baking soda, 1 tsp of protein powder, and lukewarm water. I shook it up and it is putting bubbles out.
Click to expand...
What kind of container are you using?

Are you sure the seals from the reactor to the tubing are air-tight? You could easily have a leak.

That's a pretty low ratio of yeast to sugar. I think 1 tsp to 2 cups sugar is the recommended amount, however I've not tried the protein powder receipe.

The bubbles 1 per 2 seconds is going into the aquaclear intake and being crushed in the filter.

What could be wrong?

Should I turn down the aquaclear? (Turn the power to the right)
Click to expand...
The filter may not be processing it at all. I never did get DIY to work with a filter very well. Works just fine with a stone diffuser, however.

Also, I see tiny particles/bubbles floating around, isn't that visual evidence its working?
Click to expand...
I hope you are using a wash bottle or large bubble counter inbetween the solution and the reactor? If you are not, the particles are you seeing could be yeast solution getting into your tank.

Roan
 
Roan Art said:
What kind of container are you using?

I hope you are using a wash bottle or large bubble counter inbetween the solution and the reactor? If you are not, the particles are you seeing could be yeast solution getting into your tank.

Roan
Click to expand...

Ask me how I know this is so true....no, wait, don't ask me. :(

v/r, N-A
 
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