Help with a DIY CO2

[_Nemo_]

Second time I've tried this now with no luck.

- 1 well rinsed 2L Pepsi bottle
- 1 cup sugar
- 2 cups of warm-hot water to dissolve the sugar
- 4 cups of cold water : result is 6 cups luke warm sugar water
- 1 tsp baker's yeast (stored in the fridge)
- half a dozen shakes

I have a check valve in the line to prevent the tank water from siphoning back into the bottle.

I get foam at the mix's surface but no sustained CO2 after 24 hrs. It seems as if the culture just dies off after it gets started

Tap water parameters are:

pH ~ 8.0
gH ~ 3
kH ~ 2-3

In the second attempt, I used chlorine-chloramines remover in the water to no avail.

The temperature in the house goes down to 16-17 oC during the day this time of year. Could this be the problem? Do I need to insulate?

 

[TankGirl]

My guess is that there is a leak in the line somewhere. The seal around the airline tube and the top of the jug needs to be very tight, or the gas will leak out there instead of going through the tube to the tank.

 

[_Nemo_]

Thanks TG.

I did redo the cap-line using two layers of glue just in case; in the first layer I used contact cement and let it sit for 24 hrs. In the second layer I used 'bulldog' liquid nails extended over the contact cement into the cap and line surfaces.
I'll see how this performs.

However, I imagined the vessel (mix bottle) to be somewhat under pressure even if there was a leak, no?

 

[TankGirl]

If there is a leak, the bottle will not hold any significant pressure, and when you have good bubble production in your tank the bottle should not be under tremendous pressure, since the gas is escaping, but that is why it so important to seal the cap.

When you cut the hole for the airline, it is good to try to cut it ever so slightly smaller than the tubing, so the fit is as tight as possible. Some others may have better tricks for preventing this common problem. Good luck! Once you get this going it should give you very satisfactory results.

 

[Guest]

I use these el-cheapo airline connectors to fit the cap to the airline, with a ton of silicone, of course. never had a leak or a tube blow-off, as I used to before using the connectors.

really does sound like you must have a leak. The yeast you are using is not past its expiration date? Nor is your water very warm when you put in the yeast? Too hot will kill the yeast.

 

[shawmutt]

Make the mixture (btw, I always used 2 cups of sugar). Then let it set for 24 hours. After 24 hours, if everything is sealed correctly, gently squeeze the bottle. It should feel like an unopened bottle of soda. When you squeeze a little more, bubbles should come out of the air tube in the tank. If neither happens, you have a leak.

What I did for the mixture was put in two cups of hot water, added 2 cups sugar, shook up the bottle until the sugar dissolved (I use an undrilled cap for this). Then I added 2 cups of cold water, added 2 tsp. yeast and 2 tsp. baking soda, and shook up the bottle again. Then I added the final 2 cups of cold water, put the cover on, and then set it up under the tank. Bubbles would be coming out within 24 hours.

If you find that your setup is leaking, you may want to try to make a new cap for your bottle. I drilled a hole with a bit exactly the same size as the tubing (I believe 5/8"?) and forced a piece of rigid tubing into the cap, with about an inch sticking out on either end. I ran a bead of silicone on both sides, smoothed the silicone with my finger, and set aside for 24 hours. It worked perfectly.

One site I read suggested putting a pin hole in the 2 L bottle, but DO NOT DO THIS! That tiny hole was the source of much frustration. Once I got a new bottle without a hole, it worked fine.

 

[Sati]

Do any of you have a link to a diagram of this setup, or something with more info? Sounds interesting

 

[TankGirl]

Sati - here is a link to an article describing the basic setup: http://www.littlefishtank.com/articles/article.asp?catid=7&artid=2

 

[Sati]

Awesome, TG. Thanks!

 

[OneFishTwoFish]

A quick question about the DIY CO2. Just got an algae problem and thought I might be worth the effort to give this a shot to remedy the situation. How long (days) will the mixture last. And can you/do you need to add a bubble counter to it or is that really only for fully pressurized CO2 systems.

TIA

 

[_Nemo_]

What I did is start a batch on the weekend and then another on Wednesday. I attached the two bottles to an airsotone in the tank using a T connector. They are going strong after a week now. I figured I'll change each batch after 2 weeks. This should provide a continuous (overlapped) supply.

Use a check valve.

 

[TheNewGuy]

here's another tip for those that want to do this and wish to avoid the cap seal leaks. I read somewhere that you can make a hole in the cap that is much smaller than the airline tubing and then cut the tubing at a angle and squeeze it through the hole and have it seal. keep a close eye on your ph when you first start doing this you don't want any PH swings to mess up da fishes.

 

[jhd]

This is my way of getting lots of bubbles out of yeast method within a couple of hours:

Pour 1 cup of sugar into the cup.
Fill it with warm water.
Pour approx 2 to 3 tsp of sugar saturated water from above not dissolved sugar into other cup, add 1 tsp of yeast and mix.
LEAVE IT ALONE FOR 10 MINUTES. NO SHAKING. Good reaction will be indicated by a thick foam of yeast in the cup.
In the mean time fill your 2 litre bottle with water/sugar solution and dissolve the sugar.
Add yeast and give it a shake. I keep mine in 22 deg C.
Works like a charm.