# What's more important, the lights or the CO2?



## Sharper (Oct 26, 2009)

In the past, I've always heard it was the lights. But now I hear it's the CO2.

I've been hunting for a dual tube 20" light for just a 10gal and find them way more ridiculous in price than the single tube florescent light strip. I keep wondering if I could get away with just a single tube. But I worry about being restricted to low light plants. But should I spent the extra money and just get the dual tubes and then save money by not doing the CO2? 

Or do you think low light is fine, as long as I have some good CO2? What's more important?


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## davemonkey (Mar 29, 2008)

With low light, you don't typically need CO2 if you have plenty fish to feed the plants (with waste and respiration).

When you start adding light, you increase the plants' metabolism, which leads to the potential of added nutrients (ferts and CO2). You can do this by fertilizing the water column (adding fertilizers and/or CO2) or by using an organic substrate that will provide a low-level of CO2 and feed your fish WELL to add the extra ferts.

So, both light and CO2 are important, and they need to be in balance with each other. Very low ight, CO2 from your fish is all you may need. Very high light, you'l need to be pumping in CO2. 

Did that help?


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## Seattle_Aquarist (Mar 7, 2008)

Hi Sharper,

The way I did it is I spent the money on a light (I did a DIY AH Supply kit but lurking on Craiglist is great for bargain hunters too) and did DIY CO2 until I was confident that I could really grow plants. I used Seachem Flourish for fertilizer. Then I bought CO2 equipment off of Craigslist.


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## Sharper (Oct 26, 2009)

Thank you!

This helps. I'll start off cheap with a 1-tube light and keep and eye out for something better on craigslist future in the future. I'll go without the CO2 for a while and see how things go. This will help my budget too


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## Zapins (Jul 28, 2004)

I'd say both are nearly equally important, however, without energy input (lights) plants won't grow fast or at all depending on the light intensity. Sooo, I'd have to vote lights are more important, though if you can just get medium lights and then CO2 that would be better then high lights and no CO2 or CO2 and crap lights.


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## Sharper (Oct 26, 2009)

Okay...so it's not required that I shell out $200 for lights for a 10gal. But I should put CO2 back on my shopping list. :-D


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## BryceM (Nov 6, 2005)

Low or medium light tanks with consistent CO2 are amazingly stable. I really don't know why we don't push this more as a hobby. Sure, there are a few plant species that you can't keep, but the overall experience for the average hobbyist would be so much more enjoyable and less frustrating.


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## Seattle_Aquarist (Mar 7, 2008)

Hi Sharper,

I agree with BryceM, I would do DIY CO2 with the light you have and try lower light plants like anubias and java fern. DIY CO2 is an easy fun thing to build, inexpensive, and will help you maximize your possibility for success.


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## Zapins (Jul 28, 2004)

I totally agree with the above two posts. I'd go one step further and say that you should use top soil under an inert cap with medium lights and CO2 for the most stable, hassle free, beautiful tanks. 

I have tried every fertilization method ever and really nothing even comes close to the power, price and ease of soil. You'll even be able to grow those picky plants like nesea and R. macrandra with ease.


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## bartoli (May 8, 2006)

BryceM said:


> Low or medium light tanks with consistent CO2 are amazingly stable.


Yes, I am seeing that as well in a low light 30-g walstad-tank with pressurized CO2 and CO2 controller.


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## davemonkey (Mar 29, 2008)

bartoli said:


> Yes, I am seeing that as well in a low light 30-g walstad-tank with pressurized CO2 and CO2 controller.


Are you fertilizing this tank, or only adding CO2 (plus whatever you feed your fish)?


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## bartoli (May 8, 2006)

davemonkey said:


> Are you fertilizing this tank, or only adding CO2 (plus whatever you feed your fish)?


Other than CO2, the only fertilizer for that tank is what I feed the fish.

What had prompted me to add CO2 was the yo-yo readings of pH. I have a pH monitor giving me continuous read out on the water pH. Overtime, I had noticed that the pH would stay high for no other reason than great plant growth. At other time, the pH would stay low, again for no other reason than sluggish plant growth. When the pH was staying at the high side, neon tetras didn't do well. So, I decided to use CO2 to get the pH to stay low. Tank light remains low. I did not increase fish feed. So the added CO2 did not have much impact on plant growth. But it seems to provide a much better environment for the neon tetras.


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## wi_blue (Apr 5, 2005)

Your fish and plants will love for the stable environment. Lower light and DIY CO2 with the Walstad method has work the best for me.


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