What is the option to diffuse a DIY CO2?

[gu2high]

Just set up a very simple DIY CO2 - a 3-liter bottle and a silicone tubing and a limewood airstone. Added 3 cups of sugar, 1 teaspoon of yeast, 2.3 liters dechlorinated warm water, and a handful of crushed coral. In 1-2 hours, hundreds fine bubbles per second come out of the limewood airstone, which place at the bottom of the tank below the AC HOB outlet. The water from the AC outlet blow the bubbles everywhere in the tank, however, I guess half of CO2 still escape to air.

How to improve it with a simple and cheap diffuse method to catch more CO2?

 

[neilanh]

An easy thing to do is move the stone over a bit so that it's under the intake of the HOB. This will cause the filter to suck up the bubbles, and chop them even more in the impeller. You should check your CO2 level in this configuration so you have a baseline to find out what works better and/or worse.

 

[Ketso]

This is what I was using to diffuse two 2-liter bottles. It worked well.

If you would rather purchase something instead of making it, I have read numerous posts where people think highly of ladder type diffusers.

 

[Peyton]

I made this one a few days ago. Just an old powerhead and the end of a gravel vac. The co2 levels went from roughly 20-30ppm to 80ppm. Though it really needs a prefilter as you can see.

http://i20.photobucket.com/albums/b207/peglegburnout/03032007.jpg

 

[MyCatsDrool]

Is your tank covered? One way to increase the amount of time the CO2 stays usable is to cover as much as possible. The CO2 collects in the space between the water line and the cover.

Also, it sounds to me that if you move the airstone under the intake, you will be doing a fine job of diffusing. It is virtually impossible to fully utilize CO2. You could also consider an inline diffusion method (usually on a canister filter).

 

[gu2high]

My tank is covered with glass top, but has an opening of 1.25 x 8 inches for AC HOB. After running for 2-3 hours, the CO2 level is still 6ppm (pH7, KH2), no change at all. I want to raise it between 15-25ppm level. The 80ppm level may kill fish.

I now put the airstone under the intake and almost all bubbles go into it. I guess this method is more efficient. With this low level CO2, I think it is safe to leave the bottle connected in the evening. Will check CO2 tomorrow morning.

Thank you all!

 

[MyCatsDrool]

How high is the water level in your tank also? You want it as high as possible to reduce splash from the filter. O2 introduction offgasses CO2.

I fill mine to the rim.

 

[gu2high]

I keep it one inch under the glass top, try to avoid leaving water mark on the glass top. And, it is slightly more than one inch from AC HOB outlet to the water level.

 

[Purrbox]

That's your problem. The water splashing as it returns from the HOB to the tank is gassing off the lion's share of your CO2. You need to raise the water level so that the water doesn't splash as it returns to the tank.

Also, it isn't until CO2 levels get over 100ppm that you are likely to start having problems with your fish.

 

[gu2high]

This morning, CO2 level is 10-12ppm. It is improving.