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-   -   DIY C02 Article (http://www.plantedtank.net/forums/showthread.php?t=2653)

depthC 10-09-2003 02:27 AM

Since DIY C02 is a pretty popular method of injecting C02 into small tanks 30 gallons or less I've made an article to help anyone in the process of making a C02 unit. So lets just get right into it.

First were going to need a few things to make the unit. These include:
- A drill
- A few feet of tubing
- A pair of scissors
- A sealant
- A checkvalve (optional)

http://www.freewebs.com/diyc02/tools.JPG

Now first you have to take the drill and find a bit that is just a little smaller then the diameter of the tubing (the kind of tubing you choose does'nt matter much, I used silicon because it has a little more resistance to C02 and will last a little longer than the normal clear tubing, but its fine if you choose the regualr tubing). Then cut the tubing down to the size of which it will be ran to your tank, also make sure to leave some loose tubing just incase you need to resituate the bottle or anything else dealing with the length of the tube. Then drill a hole in the center of the cap and fit the tubing in as snug as you can get it. Only put the tubing in 2-3 centimeters. After this is done you are ready to seal the cap.

So now bust out the sealant and get some in the cap against the tubing to make a secure seal. Let it sit for 30 minutes to an hour for it to dry somewhat. Then repeat the same thing for the top and let it sit. After your done sealing the tube don't mess with it much because it may move the tube and make it a less secure seal.

- Sealed Bottom
- Sealed Top

Now you may want to wait a full day just to make sure your sealant is fully sealed. Don't be impatient you'll probably end up resealing it if you do put it to use too soon.

By now you have finished making the C02 unit and you are ready to make the C02 mixture. This is what the end product should look like:

http://www.freewebs.com/diyc02/finished_diyc02.JPG

But before we jump right into making the mixture lets talk about methods of Diffusion.

There are tons of methods to diffuse the C02 into your tank. To list just a few there are:
- C02 Bells
- Diffusion Unit
- Injection into a Power Filter
- Airstones

Of course there are more but I dont want to get that detailed into the diffusion. If you are running a power filter just stick the tubing into the intake and the impellar will dissolve the C02 very well. Another easy method is an airstone, but let me tell you from my experience that it is a poor method and most of the C02 does'nt dissolve into the water. So I'd stick with the filter intake method it works great.


How To Make the C02 Mixture

Okay now to make the mixture we need a few things:
- The 2L Bottle
- Sugar
- Yeast
- Measuring Spoon
- A funnel

http://www.freewebs.com/diyc02/mixture_needs.JPG

I use the mixture of 2 cups sugar and 1/2 tsp of yeast. There are other mixtures and they have other affects. More yeast means the mixture will produce a lot of C02 but not last as long, as the yeast eats the sugar and a biproduct is the C02. So with this 1/2 a tsp it produces a constant C02 for a longer period of time, I would say for 3 weeks and the 1 tsp mixture lasts 2 weeks or less. Whatever you choose is fine, but I recommend the 2 cups and 1/2 tsp yeast.

Now take the bottle set the funnel in the top and get ready to pour in some sugar and yeast (you could use a piece of paper for a funnel if you dont have one, but i fortunately found one around the house). Now add the 2 cups of sugar, and the 1/2 tsp of yeast. Then its time to add the water. To get a good start of C02 production we want to use luke warm water, dont use hot water because this will kill the yeast. Fill the bottle with water up to the brim were it starts to curve into the top. Im not sure how to explain this that well, but just leave a 3" gap between the water level and the top.

Now you have the 2 cups of sugar, 1/2 tsp of yeast, and the water in the bottle. Find a cap and shake up the mixture well and then let hook it up to your sealed cap which should be hooked up the tank in your diffusion method that you chose. Dont leave the undrilled cap on the mixture and forget it, you will come back to a huge mess, remember this produces C02 and if its not left a point to exit it will turn into a bomb. Now that its hooked up it should take and hour or two to start producing. It may take a day depending on the temperature of water you used and if the yeast is active. Also remember to shake it up everyfew days to keep the unit producing C02.

Alrighty, you now should have a DIY C02 made up and the mixture producing. I hope this helps out anyone looking to make a cheap C02 unit. Good luck!

- depthC

Rex Grigg 10-09-2003 12:33 PM

I want to add that if you drill the hole smaller than the tubing that you don't have to use the sealant. I have made at least two dozen DIY bottles over the years and have never had to seal a single one. And I do the same with my DIY bubble counters.

Also the use of juice bottles is much better than soda bottles as juice bottles are less likely to fall over. And if you can get beer or wine yeast it's much better for long term production of CO2 than bread yeast is. I also use the jello method and a 2 liter bottle will produce CO2 for around 4 weeks.

29gallonsteve 10-09-2003 02:55 PM

For 5 dollars, you can order these from your local Hobbytown.com

http://www.hobbiesr.com/for/for-129/143.htm

There are two different sets...Red/Green are too small...Blue/Yellow are what you want.

No more silicone sealant leaks or drilling problems.

Thanks,
Steve

Guttboy 10-09-2003 11:19 PM

29gallonsteve,

I have to disagree with the use of those bulkhead fittings....they are VERY brittle and can snap easily...Trust me I went through 6 before using Rex's Idea.

Rex,

I have been using your idea without the sealant for a couple weeks now and it works GREAT! I would have never thought of that til you mentioned it! Thanks again HIGHLY RECOMMENDED!

Mike :D

metallhd 10-10-2003 12:06 AM

Well now I just have to try this no sealant thing - might I add that the addition of another smaller chamber on the side of the main bottle is useful because I have found airstones and hoses clog up with yeast gook - the second bottle ensures nothing but gas goes into the tank.

Thanks for the idea, will complain vocally if it doesn't work . . . :lol:

Guttboy 10-10-2003 12:21 AM

Metallhd,

I have another bottle on the side...just a small little water bottle that I use for a bubble counter/trap. I also do not use airstones (recommendations here) Unless you are using an airstone as the sole source of disolving the co2 I find it just an area for problems.

Mike :D

depthC 10-10-2003 12:54 AM

Ive noted in my article that you could use airstones but it is a very poor method so id recommend otherwise. As for the C02 seperation unit i used a 20oz bottle and ran the line from the C02 bottle down a few inches and the tube to the tank high in the bottle. Ive had no results at all with this and the residue still collected in the tank. I didnt use water in the unit so maybe thats the problem, any ideas why it didnt work? Since then i havent used the seperator unit because it hasnt worked the way i set it up.

- depthC

Rex Grigg 10-10-2003 03:11 AM

I have found using the standard silicone tubing that a 11/64th hole works great. You then cut the tubing at an angle and pull it though the hole. This method has sealed gas tight every time for me. In fact I used the same method to run the CO2 lines into my DIY external reactors.

aquaverde 10-10-2003 03:57 AM

I'm going to try this with some HDPE next week and see how it works.

James

Wasserpest 10-10-2003 06:37 AM

With the blue CO2-proof tubing this hasn't worked for me. It is probably too soft. Thank goodness there are many way to leakproof bottlecaps :lol:

aquaverde 10-10-2003 10:20 AM

HDPE is pretty stiff, available at the BORG or Lowe's. I think it's the best available for resisting through-wall type leakage with CO2. I expect it to work pretty well with the Rex interference-fit method, for the same reason the blue stuff would not.

Anyway, will see.

James

metallhd 10-12-2003 02:48 AM

I can corroborate the 11/64 bit size, I have also been using the flexible blue line and have had very limited success with silicone, hence my eagerness to try no sealant. I have also had limited success with the second chamber my previous post regardless - I have had the best success with going straight from yeast to tank and with no airstone.

I got some of the more rigid clear tubing at Big Al's today, will keep you posted as to its' effectiveness :)

anonapersona 10-12-2003 05:36 PM

Quote:

Originally Posted by depthC
Ive noted in my article that you could use airstones but it is a very poor method so id recommend otherwise. As for the C02 seperation unit i used a 20oz bottle and ran the line from the C02 bottle down a few inches and the tube to the tank high in the bottle. Ive had no results at all with this and the residue still collected in the tank. I didnt use water in the unit so maybe thats the problem, any ideas why it didnt work? Since then i havent used the seperator unit because it hasnt worked the way i set it up.

- depthC

There should be water in that separator, the input line is below the water, the output line is above.

You will collect something in the water, it is smelly after a few weeks. It will eliminate the slime on the gas line in the tank.

metallhd 10-14-2003 04:48 PM

I set up a new bottle from scratch yesterday, with the clear tubing I got from Big Al's - first things first 11/64 was TOO SMALL - the narrow opening pinched the hose, it was just a little too small - fortunately my drill bits are in 1/64th-inch increments, so I went up one to a 3/16 and used needle nose pliers to pull the hose through - it's tight. I have a 2 litre bottle and a 355 ml (that's 10 oz, USA) chamber bottle taped to the side - picture a hose out of the 2 litre into the small and then another coming out the small again that goes to the tank - the smaller bottle gets *ALL* the residue because it just drips out of the hose, and accumulates in the bottom, leaving only the gas to escape. It's working very well, I have a stready stream of tiny bubbles from the airstone, which I expect to remain completely clean.

The one addition I would suggest that I have not seen is a check valve - they're cheap, and you can put the bottle wherever you want then - it also seems to me that at some point there will be sufficient pressure to either a) make the bottle/lid fail (in which case it was no good anyway) or b) force the hose column back. I tell ya they're indispensible - just watch one pump short out and suddenly they seem very cheap, kinda like insurance :?

I have a question for the more experienced, though - assuming the hole is so tight that the hose needs to be pulled through, are there any suggestions as to how to open and close the bottle when changing yeast? :roll: I have been twisting it enough one way that when I screw it back on it comes out smooth, necessity being the mother of invention - is there a better way?

Wasserpest 10-14-2003 04:56 PM

Quote:

Originally Posted by metallhd
I have a question for the more experienced, though - assuming the hole is so tight that the hose needs to be pulled through, are there any suggestions as to how to open and close the bottle when changing yeast? :roll: I have been twisting it enough one way that when I screw it back on it comes out smooth, necessity being the mother of invention - is there a better way?

Turn the bottle? :lol: :lol: :lol: That is what I do :wink:

Check valve is a good idea... but also whenever I disconnect a bottle to set up new mix I squeeze the hose shut with one of those black metal springy things, that are used to clip a bunch of paper sheets together, not sure what the official name is :roll:


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