# Increasing co2 in low tech tanks



## Kubla (Jan 5, 2014)

Add a CO2 system......


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## madcrafted (Dec 23, 2017)

You can't really raise co2 levels but so much without injecting co2 into your tank. You can only increase the potential levels when in equilibrium with atmosphere by increasing gas exchange at the surface. We're talking like 3-5 ppm here. So to get the most out of atmosphere, you basically disrupt the water surface as much as possible. CO2 concentration will be higher near the surface, so good circulation is needed as well. The deeper the tank is, the lower the these levels will be, generally. This is why shallow tanks appear to have the healthiest growth in low tech environments.

Excel or other "glut" products don't increase co2 levels. They help in other ways that aren't exactly clear to me but they aren't a substitute for gas.


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## AbbeysDad (Apr 13, 2016)

Although increased CO2 in low tech tanks will sometimes produce a slightly accelerated growth (depending on light and ferts), you really don't need it. Injected CO2 is really only required in high tech tanks along with increased light and ferts.


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## Jay12 (Dec 16, 2018)

Diana Walstad has researched utilizing a mid-day siesta to increase CO2 levels in a low-tech tank. There's debate as to the credibility of the claim, but many use the technique of two photoperiods. Typically CO2 can be completely depleted in the afternoon, but with the siesta it gives time for CO2 levels to rise again.

Discussions here and here.


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## AbbeysDad (Apr 13, 2016)

You just gotta ask yourself does nature takes a mid-day siesta in order to grow aquatic plants? Yea, it's a tank of water, not nature all outdoors....but still seems to me the closer we can emulate nature, the better...just saying.


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## madcrafted (Dec 23, 2017)

Some CO2 is needed for plant growth but some species can utilize very low levels more efficiently than others, while some species even can make use of carbonates in such environments. Having said that, turning your out flow nozzle upwards or lowering water level a little is easy enough to create some surface disruption and some plants may even appreciate it. But yeah, injected co2 is not needed for many species but it could improve their structure and rate of growth... even the less demanding varieties.


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## Grah the great (Jul 3, 2013)

Guess the ammania gracilis and dwarf hairgrass I got when I was going to make this a high tech tank are toast, then...


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## tamsin (Jan 12, 2011)

Hair grass will grow low tech. You could try splitting the a. gracilis and growing half emersed that will keep you a backup supply if it doesn't like low tech.


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## Proteus01 (Mar 12, 2017)

Like Tamsin said, emersed plants will get plenty of CO2. Like madcrafted said, CO2 will be more available near the top, with some surface disruption. 
Would you be able to make a high island that allows planting right near the surface?


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