CO2 Needs for Low Light Setup?

[Uhu]

I am a newbie with a 20 gallon planted tank (Java fern, Xmas Moss, Vals, Anubias, Lobelia, Amazon Swords) under low light with a 24 watt T5 HO lamp with reflector. I noted some positive results with Seachem Excel, Iron, Comprehensive and figure I could get even more growth and less algae by replacing the Excel with CO2. I considered yeast but figured to avoid the long-term hassle and go with pressurized CO2. Am I on the right track? Would CO2 this way be overkill for my low light setup? Would paintball or standard tank be better? I'm leaning toward using a standard 5lb tank to avoid frequent fill-ups. Thanks for your help.

[Darkblade48]

Originally Posted by Uhu

I am a newbie with a 20 gallon planted tank (Java fern, Xmas Moss, Vals, Anubias, Lobelia, Amazon Swords) under low light with a 24 watt T5 HO lamp with reflector. I noted some positive results with Seachem Excel, Iron, Comprehensive and figure I could get even more growth and less algae by replacing the Excel with CO2. I considered yeast but figured to avoid the long-term hassle and go with pressurized CO2. Am I on the right track? Would CO2 this way be overkill for my low light setup? Would paintball or standard tank be better? I'm leaning toward using a standard 5lb tank to avoid frequent fill-ups. Thanks for your help.

From your lighting, I would say that you do not have a low light aquarium (but it depends on how high up you have your lighting).

You are along the right track that CO2 would be better than Excel in terms of providing a carbon source for your plants. And indeed, pressurized CO2 is less of a hassle than DIY CO2, despite the higher initial cost.

CO2 is never overkill for any aquarium; it can be beneficial even in low light aquariums, and if you decide to make a change to high light in the future, you already have the necessary equipment.

As for paintball versus standard cylinder, I always recommend to get the largest cylinder that (money or space) can afford. Larger cylinders means less time between refills, and refill costs for a 5 pound or a 20 pound cylinder do not usually differ significantly.

There are many ways to pressurized CO2; some like to buy commercially available setups, some buy from users such as myself, Bettatail or oldpunk78 that build setups, and others like to go the DIY route and piece together a setup themselves. For more information on DIY pressurized CO2 (or for general information), take a look at my pressurized CO2 article (linked in my signature).

[Uhu]

Thanks for your reply. I recently bought a single state co2 regulator from Bettatail and have already found better growth in my plants after just a few days. I think I made the right choice[censored]going[censored]with pressurized co2.

[talontsiawd]

I am with Darkblade48 in the fact you are not in the low light category. Even if you were, you would still benefit from CO2. I have actually seen some beautiful low light moss only aquariums running high CO2. Actually AFA told me they swear by high CO2 in low light moss setups.

That said, I think you will enjoy the added benefit of CO2 and a real system is the way to go. You may find your growth rate is surprising higher, even more so then adding more light would be. I just started dosing Excel in a non-CO2 tank and some of my plants are growing almost 2-5x the rate compared to before. Others only grow slightly faster but have better color. I guess my point is that even in a really balanced tank, CO2 or, in my case a carbon supplement, really goes a long way.

[exv152]

Originally Posted by Uhu

...I noted some positive results with Seachem Excel, Iron, Comprehensive and figure I could get even more growth and less algae by replacing the Excel with CO2...

I would also suggest adding NPK because you've only addressed the micro nutrients with what you're currently adding. At some point the plants will show some deficiencies, and the algae might be partly due to some low nutrients levels already.

[Chris_zx2]

I have a question regarding that. I'm hoping someone can help as I obviously have the concepts wrong.
Plant growth is a balance of macro + micro and lights. co2 promotes accelerated growth and therefore higher intake of Macro and Micro depending on if the lighting needs are met.

So if I have understood correctly, in an unbalanced tank, there is always a weakest link holding back plant growth.

Now here is where I get confused, if the lights are low and the NPK's are too high then Algae will thrive because it will be feeding on the unused NPK's correct?
Well if the lights are not the limiting the factor and there is no NPK dosing as in this case, the plants will have slow growth, but what would cause algae if there is no ferts for it? After all it is just a plant no?

Thanks!

[Darkblade48]

Originally Posted by Chris_zx2

Well if the lights are not the limiting the factor and there is no NPK dosing as in this case, the plants will have slow growth, but what would cause algae if there is no ferts for it? After all it is just a plant no?

It is very unlikely that you have no nutrients (absolutely zero) in an aquarium. Feeding fish, decomposing plant material, etc, these all contribute to a non-sterile environment that contains nutrients.

These nutrients, while not enough to sustain healthy plant growth, can be scrounged up by algae much more readily.

In fact, some algae are not plants, and are bacteria!

[Chris_zx2]

Ok makes sense but then why won't algae grow in a balance tank?

[Darkblade48]

Originally Posted by Chris_zx2

Ok makes sense but then why won't algae grow in a balance tank?

One cannot say that algae will not grow in a balanced tank; to some degree, algae will always be present.

However, healthy plants will keep the algae in check, as they are competing for nutrients and CO2.