DIY CO2 Diffusing

[maronov]

I want to try out a simple DIY CO2 for my 5.5G to see if it improves plant growth, but I'm a bit confused about methods of diffusion. I've heard that an airstone with small bubbles can do a decent enough job, but how can I tell if enough CO2 is being produced/diffused without bubble counters and other junk that I wouldn't want to buy for such a small tank?

[Mgamer20o0]

you can use the ph and kh to find the levels of co2 in your tank.

http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

[maronov]

Thanks, that's a good link! Measuring ph/kh is simple enough, but how do I then adjust CO2 levels? Can it be done with the same valve that is used to control air flow in air pumps?

[skeletonhand]

It's tough to regulate the amount of CO2 when using the DIY yeast method. The problem is that if the amount of CO2 released by the yeast cant escape through the tubing, you may run the risk of bottle failure. A nice sticky, stinky mess:eek: . The best way to regulate it would be to dissolve more or less of the CO2 in the water. If you only want a small amount of CO2, and not much of a pH drop. Use an airstone that will produce larger bubbles with less time in the water. If you want a larger amount of CO2, and the pH to drop further. Try getting a glass diffuser, and increase the amount of contact time the bubble have with the water.

[maronov]

Thanks everyone! Final question (hopefully)... slightly unrelated. How long does a standard DIY 2-liter soda bottle yeast/sugar solution last (how long does it produce constant CO2 levels)?

[$eaba$$]

For me, around two to two and a hlaf weeks. It still goes a little after that, but starts to slow down.

[kooter]

Thanks, that's a good link! Measuring ph/kh is simple enough, but how do I then adjust CO2 levels? Can it be done with the same valve that is used to control air flow in air pumps?

There are lots of things you can do to slow the production down, the only thing to do to speed up production is to add another 2L. To slow down the co2 (without compromising the diffuser), is to add either an inline t connector with a valve that can open close or a 2 way gang valve.
Check out some interesting inline hose accessories here! I love the one that shows the red ball going round and round to visually show you the amount of gas going through the tube!

http://www.dynamicaqua.com/tubing.html