# DIY co2 and liquid co2 together or not?



## Mycoal_Win (Feb 5, 2015)

Hi!

TANK SPECS:My tank is a 20 gal long. There is DHG in it that was introduced about 4 days ago. It has a 30 Aquaclear with a corner sponge filter rated for 10 gallons. Substrate is eco complete on the bottom with about 1-2 inches of regular PetSmart sand on top. Water conditions- I cannot say because I don't yet have a water testing kit, but will definitely get one.

QUESTION: I had API liquid carbon around and was dosing that the first few days (2mL) daily. Then I decided that I would rather have diy co2 because it seems more practical if I wanted to have co2 and it would be more economical. Should I continue to dose my liquid carbon or not? If so, should I continue to use 2mL or should I lower this? Also, my DIY co2 produces about 2 BPS. I want to make sure I'm not doing too much that would essentially gas any future fish in the tank.

PS: My sponge filter is off or very low during the day to reduce surface agitiation so I can get most of the co2 diffused. Currently using cotton swab to diffuse it under my HOB because I broke my glass diffuser ):


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## Diana (Jan 14, 2010)

You can do both. 
As for what your tank needs, it depends on several things. 

1) Usually DIY yeast/sugar is a fairly low pressure system, so needs some work to properly disolve it in the water and disperse it in the tank. Even in a well designed system it usually does not supply all the CO2 the plants can use. They are not usually stable enough that you can count on 2bps all the time. That is probably not enough to gas the fish in a 20 long, because of the poor distribution. 

2) A slightly higher end 'low tech' tank may also have more fertilizer, or more light. So the carbon needs of your plants could be higher than the average 'low tech' set up.


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## Mycoal_Win (Feb 5, 2015)

I mean my co2 diffusion method isn't the most orthodox but I do plan on getting a different diffusion method to better diffusion. I understand that diy co2 isn't stable but I mean my I'm currently running two 2 liter bottles with 2 cups sugars and water and It has actually been slightly stable for me. I use a control valve and I keep it kind of closed. This allows for a slight buildup in pressure, but nowhere enough to blow up. I will be changing one bottle every two weeks to keep that constant pressure. Hopefully this delivers.


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## burr740 (Feb 19, 2014)

- As mentioned in the other thread, if you do it right the AQ30 will offer excellent diffusion. Reactor level efficiency, you dont need another method.

- I always use a liquid carbon source in addition on any tanks with DIY co2, primarily to help prevent algae, because even the best DIY systems will have their minor ups and downs.

- To avoid algae problems with DIY systems, it is critical to maintain a consistent rate of production over the long haul, from one day to the next. Using 2 bottles, you should change out one bottle every week, not every two weeks. Two weeks is about the maximum a sugar/yeast bottle will run at a consistent rate. Although it may produce bubbles for four, six or even eight+ weeks. That is not the point. As soon as the bubble rate starts to slow down it's time to replace the mixture - ideally just before that. Changing one per week means each bottle is getting changed every two weeks.

- There are a couple links in my sig that may offer some useful info.


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