Are co2 systems required for live plants?

[Hebdizzle]

I never quite understood.
I was planning on growing a couple plants in my 10 gallon but if this expensive equiptment is needed....

thanks for the help

[superjohnny]

It really depends on the kind of plants you want to grow. From what I've heard Java moss & Java fern are pretty easy to grow in low light tanks. CO2 is definitely not necessary, but it certainly helps plant growth.

[BumBumBee]

Is co2 bad for Algae? Does it keep it from growing?

[RTR]

Plants are just over 40% carbon by weight. Submerse plants get their carbon from CO2. But you do not necessarily require a pressurized or even DIY fermentation CO2 system. With moderate light and moderate feeding, paired with avoidance of excessive water surface disturbance, in-tank generated CO2 will be sufficient.

CO2 does not keep algae from growing. Avoiding algae means balancing plants, lights, and nutrients - excesses or lack of any of those can promote algae.

[AntmanMike]

CO2 prevents algae from growing indirectly. If you have many nutrients but not enough CO2, the plants can only use so many of the nutrients. The remainder go to algae. If you have enough CO2 in your system, your plants can make full use of ALL the nutrients, therefore depleting the algae of vital nutrients.

[BumBumBee]

Can the plants use the nutrients faster than the algae? Why wouldn't the "balance" be equal amounts of plants and algae growth?

[Robert H]

The ideal amount of C02 needed for plant growth in a moderate to bright light tank is between 20 and 30 parts per million.

The maximum amount of C02 you can measure in a tank produced naturally by the fish population and bacteria and decaying organics is only 2 to 3 ppm. That is a huge difference. Current or no current.

Some plants can adapt to very low C02 levels or derive it from the KH of your water, but many of the plants we use in our aquariums are tanken from nature where they grow to the surface or out of the water and obtain C02 from the atmosphere. These plants will struggle in a tank which does not have C02 fed into it.

Very slow growing plants like Anubias, Cryps and ferns can survive or even grow without adding C02, but even these plants will grow much more robust and more quickly with elevated C02 levels.

[superstein61]

Originally posted by Hebdizzle
I never quite understood.
I was planning on growing a couple plants in my 10 gallon but if this expensive equiptment is needed....

thanks for the help

I have a whole tankful of plants that I am gronwing in a Non-CO2 added tank. Growth is slow but healthy - so yes, you can grow plants in such a setting.

If you are only looking at a couple of plants - just pick the right ones - I'd suggest some that have been mentioned - Anubias, Java Fern, Java Moss - and they will do ok in your low light, non-co2 tank.

[RTR]

Atmospheric equilibrium for CO2 at sea level is close to 5ppm. Fish and bacterial CO2 production within the tank will boost this if it is not blown off.

Higher elevations - in the Rockies, etc. - will have lower equilibrium points.

Moderately lighted tanks do not, repeat do not, require 20-30ppm CO2 to be successful. High light tanks do need this supplement.

Do not accept the commonly stated or implied "fact" that you cannot have a successful planted tank without pressurized CO2.

[Heady]

In many threads I have seen people suggest that water surface disturbance drives out CO2. However, I am told the water surface disturbance is what dissolves O2 in the water, keeping the fish alive.

So, when you eliminate water surface disturbance, are you also limiting the amount of oxygen available to fish?

Also, is there a CHEAP way to add CO2 to a large tank (100 gal)?

[AntmanMike]

CO2 = Plant Growth
Plant Growth = Plants make O2
CO2 = Plants make O2

[RTR]

Heady - I have two dozen tanks operating right now, the majority planted. None of those tank has an airstone, and HOB filter, a biowheel, or any other device requiring surface breaks. My fish are healthy and happy, my plants are healthy and happy, and my inverts are healthy and happy. You need circulation/current, you do not need surface disruption.

[Heady]

RTR, do you have CO2 injection?

Is there a cheap way to use CO2 in a 100 gal?

[Robert H]

Robert, Tom Barr has been able to show that even plants under low to moderate light use about the same C02 levels, 20 to 30 ppm...some people go as low as 15ppm. (For maximum photosynthesis)

In order for plants to go thru phosynthesis, there has to be enough C02 to saturate photosynthesis.

"At air equilibrium, the concentration of CO2 in air and water is approximately equal at about 0.5 mg/L. Unfortunately, CO2 diffuses about ten thousand times slower in water than in air. This problem is compounded by the relatively thick unstirred layer (or Prandtl boundary) that surrounds aquatic plant leaves. The unstirred layer in aquatic plants is a layer of still water through which gases and nutrients must diffuse to reach the plant leaf. It is about 0.5 mm thick, which is ten times thicker than in terrestrial plants. The result is that approximately 30 mg/L free CO2 is required to saturate photosynthesis in submerged aquatic plants."

That is a quote from David Huebert.

I agree you do not have to inject C02 to grow plants. Being "successful" is highly subjective. There is no doubt at all that any plants will grow much more healthy, vibrant looking and at a faster rate by injecting C02, and some plants, not all...but some, are virtually impossible to grow without it.

If you are not going to inject C02, you have a much better chance with slow growing plants or plants that may derive C02 from the KH or from their roots, but that still doesn't change the fact there would be a significant difference if you brought the C02 level up to at least 15ppm if not higher.

Plants that are actively going thru photosynthesis release more oxygen, which is also very beneficial for the tank and even helps to cut back some algaes.

Don't let C02 scare you away from growing plants, but make the step to C02 when you feel ready and want to see improvements in how your plants grow, and be able to have a wider choice of what plants you may grow.

[Tempest]

Heady- If you are going to the expense to set up a 100 gal tank, then the compressed CO2 is the route to go in my opinion. I don't think any DIY is going to be sufficient. I think I saw that Aquabotanic is having a sale on systems or at least part of the system. Florida Driftwood also has a comparable system. With such a large tank, you will probably have a canister filter and you can look on the DIY section of the Aquabotanic forums for several methods of injecting CO2 using reactors externally which use parts you can get at a hardware store. (Much cheaper than buying a reactor premade)

[RTR]

In hobby tanks there is no requirement for photosynthetic saturation. This is part and parcel of the current US madness that unless your tank is operating on a knife-edge of very high light, very high CO2, very careful macro- and micronutrient supplementation, massive weekly prunings and equally massive weekly water changes, then you are not doing it right, and are a total failure at growing plants. Horsefeathers! Yes, it is quite impressive to see tanks looking like fizz factories, but you have to ask yourself if this is to be your goal. Submerse aquatic plants can and do grow quite well with moderate light and CO2 conservation. Why should they have photosynthetic saturation? Is maximum growth rate your goal? It is not mine, has never been, and is unlikely to ever be so. My goal is attractive fullly planted tanks which show off my current favorites of species tanks of schooling fish, and in which they will be comfortable and live long healthy lives. To say that I need to drive those plants at top speed or I do not know what I am doing and am doomed to failure is tunnel vision under the influence of the most popular US style of the moment, and is simply not true.

Yes, I freely admit that CO2 supplementation is beneficial at all light levels. Whyever would it not be? My first post in this thread was to that effect. But 'beneficial' and 'required' are two different words with radically different meanings and implications. Beneficial does not mean required.

Some of my swordplants are themselves or are decendents of plants I bought over 20 years ago. My current vals are largely decendents of plants from the same era, ditto the Anubias (I use it for carpets and have literally square yards of the stuff), and some of the crypts are almost as old in lineage. I doubt my Crinums are nearly that old, as I have cleared them out a couple of times as they are such space and light hogs. I do not consider this failure to grow and maintain healthy plants. I don't have algae problems - a number of my tanks have never even had ANY hard green spot algae. Goodness gracious, wherever did I go wrong? :rolleyes:

They are several years old now, but browse through Takashi Amano's first three books - check out the lighting he used then, especially on the larger tanks, and the CO2 supplements. I doubt seriously if he would still suggest the same practices as he has become an industry, but his lighting was moderate and CO2 the same, if any. Those tanks made him famous. Too bad he did not know he was doing it "wrong".

BTW:

"The solubility of Carbon dioxide in cold water is 171.3 cm3 per 100 cc of water. This is quite a high solubility. Oxygen for example has a solubility of 4.89 cm3 and nitrogen has 2.33 cm3 per 100 cc of ordinary cold water. Oxygen, Nitrogen and Carbon dioxide are the three major constituents of air but due to very high solubility, carbon dioxide gets easily dissolved in water."

Heady: I do have a compressed gas system - in storage in the garage. I played that game to test it, but decided it was not needed for my practices and purposes (below ~3W/gallon). Similarly, I have Carbo-Plus units, also in storage, and have tested DIY CO2. At my operation levels, they are not necessary. The latter two would be inappropriate for a large tank in any case. I like to understand how things work, and test a great many things I do not end up using routinely. Currently I am playing with SeaChem's Excel supplement - in one new setup and one established tank. When it came out I did not give it much of a trial, too hap-hazard to be satisfactory to me. Now I'm looking at it a bit more carefully. I doubt I will ever use it routinely, but it is too early to judge.

[superjohnny]

*Note to self* If ever in Maryland track down RTR and go check out his fish tanks.

[Heady]

RTR that was a great post. It's refreshing to hear some well-thought-out responses every once in awhile instead of the usual one-liners.

I'm glad someone else feels the way I do about CO2. I wouldn't mind having a lush garden in my tank in short order but I probably wouldn't be excited about all the pruning etc that goes with it. I just want my plants to be healthy and my plants to look nice. If I wanted a farm, I would buy acreage. ;)