Making A DIY C02 Unit and C02 Mixture Article

ishar

MFT Staff
Jul 27, 2007
1,490
0
36
33
Hamilton, ON.
ok, well I had a bad seal apparently, as I found out when the tank water backed up into the bottle and then was leaking out :S. I did a 75% water change and I hope nothing bad comes of it. I am resealing the cap now and then hopefully it will be good to go next time :p
 

cchase85

Large Fish
Jun 6, 2006
446
0
0
35
New England
I threw mine together a few weeks ago in about 20 minutes.

It took mine a few hours to start producing ubbles, and over the course of the next week the rate at which it bubbled continued to increase until it was quite a bit (in my largely uninformed opinion) of bubbles...

I put a check valve in mine so that tank water could not back down into the pop bottle.
 

ishar

MFT Staff
Jul 27, 2007
1,490
0
36
33
Hamilton, ON.
well I resealed it and really gently hooked it back up as it seemed like the yeast was producing a lot of C02, and I thought it would be good to check the seal. So I did that, but the only time bubbles would come out was when I had the bottle on top of the tank, and even then it was less than one bubble per 5 seconds. Then when I shook it it came out at about 3 per second.

Should I just let it sit on the tank stand and let it build pressure or what should I do?
 

ishar

MFT Staff
Jul 27, 2007
1,490
0
36
33
Hamilton, ON.
lol ok. So the only reason it wasn't working was because I am impatient :p. The broken seal was the first error, then when I set up the second try, I just didn't wait long enough for it to happen I guess :p. It is working now at about 1 per 10 seconds, but I assume that rate will go up in a bit. Thanks cchase.
 

Big Vine

Elite Fish
Feb 7, 2006
3,895
9
0
44
Florida
The bubble-rate should go up over time.
As for positioning the CO2 bottle---I'd say definitely under the stand (or at the very least below the level of the tank). The mixture will give off more than enough pressure to put the CO2 into your tank without being positioned above tank-level. Even with a check-valve I think positioning it above the level of the tank is just asking for trouble. That said, a check-valve is still a very good idea, like Chase said---you do not want tankwater flowing down and into your mixture bottle either!

BV
 

ishar

MFT Staff
Jul 27, 2007
1,490
0
36
33
Hamilton, ON.
wait... why wold it being above the tank be bad?? CO2 is more dense than air so it sinks, so if the bottle was above it would be easier for the CO2 to go down the tube...
 

Big Vine

Elite Fish
Feb 7, 2006
3,895
9
0
44
Florida
And also I like to give the bottle a shake every so often to keep the CO2 flowing steady---even with a check-valve in place I'd still be very concerned about any mixture flowing down toward the tank. Like Lotus said, any mixture in the tank will lead to problems---could be disastrous!

BV
 

tom91970

Superstar Fish
Jan 2, 2007
1,305
5
38
Tejas
www.myspace.com
I started my own DIY project last night. I actually started this project over 6 months ago, when I drilled the hole in the cap, but never got the project up and running.

Anyway, last night (around 9:00 pm) I mixed the sugar (2 cups) and yeast (1/2 tsp) with lukewarm water. I placed a check valve about 18 inches from the cap and ran about a 4 foot section of air line to my intake filter. I will probably hook it up to a gang valve soon...maybe not.

Right before midnight (1/1/08) I could hear the impeller chopping the bubbles up. So, it too about three hours for the CO2 to start producing. I hear the chopping sound about every 20-30 seconds.

I checked the pH at 10:00 am the next morning and it remained at 7.6. I will check it again tomorrow and so forth.

As far as placement of the bottle I have it right next to the tank (which is 14gallons,btw). I have no where above the tank to place it. Do you think placing it two feet below would be a bad idea?

Any input or ideas? Suggestions?
 

tom91970

Superstar Fish
Jan 2, 2007
1,305
5
38
Tejas
www.myspace.com
It's actually better to have the CO2 bottle below tank level, in case it gets knocked over.
Thanks. It's now sitting underneath the tank. I also installed a gang valve in addition to the check valve. Right now I'm trying to get it adjusted just right. At this time it's sputtering about every 25 seconds rather than every 5.

My cabomba appears to be pearling now' I've seen five or six tiny bubbles on a few of the leaves. I'll give it some time to be sure.
 

alter40

Superstar Fish
Nov 26, 2007
1,293
0
0
37
Charlotte, NC
Maybe you had the bottle filled to the top or you had your airline going down into the mixture itself. There should be a few inches of just air between the mixture and the top of the bottle and they your airline should just barely go into the bottle.
 

ishar

MFT Staff
Jul 27, 2007
1,490
0
36
33
Hamilton, ON.
I am not entirely sure, but I don't think it would help. If you upped your lighting then maybe, yes it would be useful, but at .5 wpg on a 40G I don't think CO2 will help you out much.
 

epond83

Large Fish
Mar 11, 2007
483
0
0
Hey i was wondering how long it will take to drop the pH? I was told by my fish store (personal owned non chain good place) the Kh ans Gh are kinda high and kinda hard so i know it won't drop to much, but i'm wondering if maybe i need two 2 liter bottles since i have a 40 gal.

I have the tube hooked up to the intake of a powerhead which seems to put out a fairly fine mist about every three seconds or so, it's been running for 3 days now.

My pH was maxed out on my chart of 7.6 and seems to maybe be like 7.5 but doesn't seem to have really changed

oh yeah I'm at 1wpg now.