Question about the use of Co2

[The Sandman]

Ok here's the thing, Ive recently started to grow plants in my 20g tank with reasonble success but they could do with a boost, a Co2 injection. I constructed the DIY Co2 system as explained on here but am uneasy about using it.

The problem is that ive read loadsa aquarium books and all of them emphasize on having a well oxygenated tank for healthy fish. I have it in my head that the Co2 will suffocate my fish. Is there a certain (maximum) amount of Co2 recommended??

If it helps i have a 20g tank with two 14w lights and the following fish:

12 guppies
2 Cories
2 black widows
5 Neons

Any help/advice is greatly appreciated.
Thanks

 

[sinistral]

What kind of plants do you have?

Depending on what plants you have, I actually think that you may do better to increase the amount of light first, prior to adding CO2. Getting the wattage up to 2 or 3 watts per gallon (40-60 watts of light total over your 20g tank) might provide the boost you need over the 1.4 wpg you have right now.

If you are set on adding CO2 to the system, most of the faqs I have read on thekrib suggest a dissolved CO2 content of 15 ppm. As far as I can tell, people suggest that dissolved CO2 of less than 40 ppm is considered safe for fish, although I have read an article or two that suggests fish can do well with levels much higher than this. You can titrate how much CO2 is emitted from the regular DIY soda bottle rig with a clamp partly occluding the airline output.

If you are unsure about how to calculate CO2 levels (there are also tests available), or if there are other things you're curious about CO2 injection, I'd really recommend you read this faq from thekrib website.

I would also highly recommend reading Karen Randall's article on balancing lighting, CO2 and fertilizer in the aquarium.

I hope that's helpful. You might consider posting in the planted tanks section too for other replies. Best of luck~

 

[foty89]

The amount of light is a very important consideration.

Also, I would not worry about your fish, as you stated that it is a DIY solution. It would be very difficult, if not impossible to get enough CO2 out of a DIY to kill your fish.

 

[houndour]

Hi,

I'm not an expert about plants, but have been doing loads of research to set my tank (I've only had my plants since Saturday). I was advised that if you have 3 watts of light per gallon or more then to provide CO2.

I've got a 19UK gallon tank and have 55 watts of light and I bought the Nutrafin CO2 system (which I will use my own DIY mixture when my sachets run out).

So I have to agree with sinistral and go for lights first.

There are also loads of posts in the DIY section about DIY Co2 if you havent been there already.