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How important is CO2 for a planted tank?


Alec
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Co2 is essential in a planted tank, but whether you should artificially introduce more depends entirely on what plants you want to grow and what your goals are.

 

You can grow a great variety of plants without having to inject co2 into your system, and many shrimp tank keepers prefer using what have been dubbed "low tech" plants. What kind of light will you be using? Are you planning on using a nutrient rich substrate such as ADA Amazonia, Controsoil, Tropica soil, etc? What kind of shrimp are you going to be raising?

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2 hours ago, Alec said:

I was planning on starting out with aqueons clip on planted light and use aqueon shrimp and plant substrate. As far as the shrimp, most likely cherry shrimp and/or color variants. 

If you're going to be raising neos, I'd suggest going with an inert substrate. Something like Eco Complete or sand. They like having some KH in the water and the shrimp and plant substrate will strip it out of the water. And unless you're using remineralized RO water, you'll fluctuate the KH every time you do a water change which is detrimental to the shrimp (I know from experience).

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CO2 isn't needed at all, the main impact it has is how quickly nutrients are consumed by the plants. I've kept shrimp with and without CO2 and it only really affected the plants since I was only using low amounts (max 2 bps). Even carpet plants will grow out without injections but it takes significantly longer. Another thing that few people mention is that while plants grow faster with CO2, they also die faster and require more maintenance.

If you're new to planted tanks, I'd recommend investing money into fertilizers/water chemistry and a light like a Stingray or a 3.0 before getting into CO2.

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3 hours ago, varanidguy said:

If you're going to be raising neos, I'd suggest going with an inert substrate. Something like Eco Complete or sand. They like having some KH in the water and the shrimp and plant substrate will strip it out of the water. And unless you're using remineralized RO water, you'll fluctuate the KH every time you do a water change which is detrimental to the shrimp (I know from experience).

Thank you! So, if I were to go the sand route, would the live sand from caribsea work? Also, I'd be using conditioned tap water. How would that most likely affect KH?

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Co2 is essential for plant growth. However, injecting additional co2 in a tank is not necessary. Co2, nutrients and light are the three metrics we can balance in a planted tank. It's necessary, but in a tank that isn't injecting co2, we're relying on the background levels present in the water. 

All tanks have some co2, just like the water has some oxygen saturation. If you have lots of fish (like 100 guppies in a 50 gal), you'll get s slightly high co2 level from the guppies breathing, and the amount of co2 they put off might be equal to low level injecting. So if your question is do I need to add additional co2 in the form of pressurized or passive co2, the answer is no. Planted tanks can be successful without. You just need to balance your lights and ferts to match your co2 levels.

6 hours ago, varanidguy said:

I was planning on starting out with aqueons clip on planted light and use aqueon shrimp and plant substrate. As far as the shrimp, most likely cherry shrimp and/or color variants. 

The pelleted aquasoils (aqueon plant substrate, fluval stratum, tropica aquasoil, ada amazonia, the list goes on) will almost always lower your ph and buffer the water to soften it over time. They're all a little different in nutrient levels and ingredients, but generally all a good choice for plants. Neos can do well on it provided your water has some GH and KH. Sand can be difficult to grow plants in. You'll want to add root tabs regularly. It's been my personal experience that plants develop better root systems in a pelleted aquasoil compared to sand. Eco complete is also an okay choice. It's just little pieces of lava rock, totally inert. 

3 hours ago, Alec said:

So, if I were to go the sand route, would the live sand from caribsea work? Also, I'd be using conditioned tap water. How would that most likely affect KH?

It'd be good to know the parameters of your tap water. If it already has GH/KH, then no need to buff it further. Test your tap water, or bring it to you LFS and ask them to test GH and KH and well as nitrates. nitrites and ammonia.

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9 hours ago, Alec said:

Thank you! So, if I were to go the sand route, would the live sand from caribsea work? Also, I'd be using conditioned tap water. How would that most likely affect KH?

Which live sand are you referring to? As long as the sand is inert you'll be fine. If it's "live sand" like what's commonly used in saltwater, you'd want to avoid that as well, as it will buffer your pH, and hardness levels, higher. Do you know the parameters of your tap water? GH, KH, pH and if it has anything else in it like phosphates, ammonia, or nitrate as well as the TDS?

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While it is needed, you don't have to inject it. 

There are a few different ways you can get it.

1.  In dirted tanks, you will get it via gas release through decomposition in the soil.

2.  You will get some through respiration of your aquatic animals.

3.  You will get a fair amount through the gas exchange that occurs at the surface.

4.  You can introduce it passive diffusion via something like a CO2 bell.

5.  You can introduce it via injection.


I personally do like passive CO2 in my own setups.  Here are two great videos:

 

 

Edited by Ben_RF
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Oh and a thought if you do decide to go the passive route. 

Based on my own experience, I find if I am doing passive CO2 that if I add an airstone to the setup (35g or less tanks) I will drastically reduce how quickly the CO2 dissipates from my bells.   

Some measurements I did using the same 20 gallon planted tank.

Using a hang on the back filter and a 250 ml bell for CO2l, it took approximately 4 1/2 to 5 hours for the CO2 to dissipiate out. (repeated daily for 30 days with the same result)

Using a sponge filter with a never clog air stone and the same 250 ml bell for CO2,   it took approximately 9 hours for the CO2 to dissipiate out.  (repeated 30 days with the same result)

Using a hang on the back filter, air stone, and the same 250 ml bell for CO2, it took approximately 9 hours for CO2 to dissipiate out. (repeated only for 20 days with the same result)

So with all that being said, this is why when I run passive CO2 I make sure to have an air stone in the tank.  If I am not doing passive CO2 but I do have some plants, I do make sure to keep an air stone going as it does seem to introduce some CO2 to the tank.

Edit:  A list of plants that are in that 20g.   Java fern, anubias coffee, anubias nana, dwarf sagitteria, broadleaf sagitteria, anacharis elodae, dwarf aquarium lilly, and frogbit. 

Edited by Ben_RF
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9 hours ago, varanidguy said:

Which live sand are you referring to? As long as the sand is inert you'll be fine. If it's "live sand" like what's commonly used in saltwater, you'd want to avoid that as well, as it will buffer your pH, and hardness levels, higher. Do you know the parameters of your tap water? GH, KH, pH and if it has anything else in it like phosphates, ammonia, or nitrate as well as the TDS?

So, I'm not sure. I will have to get a GH, KH, TM test kit. 

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