# co2 and low light



## hixy (Dec 7, 2003)

hello folks is it worth using co2 in a low light aquarium 

thanks hixy


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## distrbd (Feb 17, 2006)

No ,It would invite algae.
With low light you should not even fertilize .


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## Rex Grigg (Dec 10, 2002)

That's not true. CO2 will help even in low light situations. And you should fertilize even low light tanks in many cases.


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## distrbd (Feb 17, 2006)

I was only referring to the non co2 method advocated by Tom barr where there is no need to do water changes and fertilizing and no co2,and I have been trying this method with a 90 gal. tank but since it has only been 3 weeks using this method ,I would leave it to your judgement to whether to add co2 or ferts. 

Barr Report - Non CO2 methods


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## aquamoon (Jul 26, 2004)

> I was only referring to the non co2 method advocated by Tom barr where there is no need to do water changes and fertilizing


Unless I mis read the article. Mr. Barr does sugest that ferts will improve plant growth.


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## distrbd (Feb 17, 2006)

aquamoon said:


> Unless I mis read the article. Mr. Barr does sugest that ferts will improve plant growth.


A copy and paste from the article:
No dosing? Generally yes for many easy to care for pland species(I'll discuss this much more later), the fish waste represents the dosing and you feeding them daily adds the nutrients.


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## magicmagni (Nov 7, 2003)

Wow I don't remember that part, but I know he does go into a dosing routine in that article as well for low light/ no Co2. I think some kind of dosing is helpful just not as much.

Low light planted tank with Co2. I have had awesome results myself. I think the best planted tanks I did were low light with Co2. Plants grow slower so your arrangments stay in place the way you want them for longer (although it takes longer to grow in) and there is a lot more forgiveness when it comes to dosing, meaning that you can get away with a lot more and not get an algea bloom/ stunt plants.

I treat LL/C02 much the same way I do a higher light tanks, except that I may not dose as frequently- like only onceor twice a week and dose to accomodate the slower growth rate, but I still shoot for the same nutrient levels as the higher light tanks. I think you can change the water less too, but I tend to still do weekly water changes since I'm doing the other tank anyways. 

You'd be surprised what you can grow with low light/ co2. I'm growing HC currently in my low light tank. I've also grown glosso, hairgrass and tennelus. One thing to be aware of though is shadowing them with other plants. This may be were folks have problems as with the low light you need it all to get to these plants.

Co2 will not hurt at all it will only help even if only yeast type.


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## mikey (Mar 14, 2004)

Hey Magicmagni,

How many wpg are you using in your low light? I just turned on my co2 again in a low (1.3 wpg) light tank.


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## distrbd (Feb 17, 2006)

magicmagni said:


> Wow I don't remember that part, but I know he does go into a dosing routine in that article as well for low light/ no Co2. I think some kind of dosing is helpful just not as much.
> 
> Co2 will not hurt at all it will only help even if only yeast type.


Yes that advice was not baseless.
I am trying very hard not to use co2 and ferts in my 90 gal low light tank just to see if the fish load is going to be enough to supply the nutrients and if not ,add a few more fish.I must admit ,I have been tempted to use some NPK ,but so far the growth is more than acceptable.


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## magicmagni (Nov 7, 2003)

mikey said:


> Hey Magicmagni,
> 
> How many wpg are you using in your low light? I just turned on my co2 again in a low (1.3 wpg) light tank.



Not as low as that. Right now my low light 10 gallon tank has two of those screw in incandesant energy savers type bulbs. About 36W total, but as you may know on smaller tanks the WPG is out the window so I consider this tank low light especially considering it has no reflectors and half the light shines through the top cooling vents of the hood.

The tank I had before this was lower light- a 35 gallon 36" deep hexagon with 2 18W NO flouescents. Grew dwarf sag and ferns/ moss in there. I didn't use Co2 at first but was very pleased with the results and was later able to put riccia in there and it grow ok, but not the best.

That's great you put the Co2 back on. You don't have to use it, but if you have it why not? Unless you like the challange of growing plants w/o co2.


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## magicmagni (Nov 7, 2003)

distrbd said:


> Yes that advice was not baseless.
> I am trying very hard not to use co2 and ferts in my 90 gal low light tank just to see if the fish load is going to be enough to supply the nutrients and if not ,add a few more fish.I must admit ,I have been tempted to use some NPK ,but so far the growth is more than acceptable.


That's cool. It just all depends on what you want. Sometimes dosing a little will not hurt, but not dosing at all may be ok too; however the nutrients have to come from someplace be it from fish food/ waste or inorganic ferts. The plants don't just magically grow LOL. If you need more nutrients for the plants you don't even have to add more fish if you don't want. You can just add more fish food. This is what Dianna Walstad discusses in her book. Actually she kinda describes feeding a certain amount based on tank size/ plant demand and not necessarily fish stocking level although in all cases fish have more then enough food and are generally fat and happy.


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## faltered (Mar 8, 2006)

Check out the Low Tech Forum- lots of people doing something similar.

I've had my tank set up for about three to four weeks, no CO2 and the plants seem to be doing well thus far.

It can be done, just test it out.


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## fresh_lynny (Mar 9, 2006)

Yes it can be done...i read the thread, and I think the disconnect is that someone said CO2 in a low light tank will promote algae...that simply is not the case. It doesn't mean that it is necessary or not necessary, just that CO2 injection will NOT promote algae~

Tom will always promote fertilization of some sort. It depends on the fish load and the plant species you have chosen. All have differing needs. you have to test your individual milieu....fishload, plant species, light...etc before you can say no fertilization is necessary. i think everything can benefit some sort of fert schedule. Toms says even a once a week macro/micro will help.


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## distrbd (Feb 17, 2006)

Co2 is a nutrient. if the tank with low light is balanced without ferts&co2 ,then what would happen if you add more nutrients than the plants can take up?
I remember Tom was advising a member who had algae problem in a low light tank not to do water changes(amongst other things , likelower the fishload) because fresh water is rich with co2.I will look for that thread ,it wasn't more than a week ago.


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## distrbd (Feb 17, 2006)

Here it is:

Quote from Tom:
The water change flushes the tank with lots of fresh CO2 rich tap water.
This one time flux once a week favors the Algae, BBA likes slightly higher CO2ppms, around 5-10ppm seem optimal and flowing water.


http://www.plantedtank.net/forums/low-tech-forum/33636-easiest-method-dealing-bba-low-tech.html


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## yoink (Apr 21, 2005)

I use co2 in a low light tank. The growth is better with co2.


distrbd said:


> Co2 is a nutrient. if the tank with low light is balanced without ferts&co2 ,then what would happen if you add more nutrients than the plants can take up?


If it is co2, it will outgas. You should be doing enough water changes on a tank with co2 to get rid of any excess ferts.



distrbd said:


> Here it is:
> 
> Quote from Tom:
> The water change flushes the tank with lots of fresh CO2 rich tap water.
> ...


This advice does not apply if you are using co2.


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## Naja002 (Oct 12, 2005)

> I treat LL/C02 much the same way I do a higher light tanks, except that I may not dose as frequently- like only onceor twice a week and dose to accomodate the slower growth rate, but I still shoot for the same nutrient levels as the higher light tanks. I think you can change the water less too, but I tend to still do weekly water changes since I'm doing the other tank anyways.


Same here, except my water changing schedule has gone to +/-2wks. Next I will move it to +/-3wks, and then maybe once a month.



> Here it is:
> 
> Quote from Tom:
> The water change flushes the tank with lots of fresh CO2 rich tap water.
> ...


The issue is the C02 fluxuation. Using C02 on a regular, on-going basis does not have the same effect. Its the very low C02 level that is changed with the influx of "New" water from the water change. C02 and low-light go well together--atleast that's My Experience.


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## fresh_lynny (Mar 9, 2006)

I think Tom's statement is taken out of this context. 

*ahem* Tom care to respond? I think many of us believe a low tech tank benefits from CO2 and ferts <including you> ...and some are of the belief that it causes algae and basing it on your comment.


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## Naja002 (Oct 12, 2005)

Nothing in the article alludes to C02 causing algae in low-light tanks.

and

The plants have to be fed, and the first attempt at that is a balanced fish load. Next is the addition of ferts--if necessary. 

The article is clear.

And Tom's explanation of bba in a low-tech being caused by water changes is clear also---RE: easiest-method-dealing-bba-low-tech

Tom has said for a long time that rapid change in C02 levels has ill effects--That's what a water change in a low-tech system does--rapidly increases C02 and then it bottoms out again as it degases. Low to High to Low again--favors algae, not plants. Continuous C02 supply is not the same thing. Apples and Oranges.


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## plantbrain (Dec 15, 2003)

distrbd said:


> I was only referring to the non co2 method advocated by Tom barr where there is no need to do water changes and fertilizing and no co2,and I have been trying this method with a 90 gal. tank but since it has only been 3 weeks using this method ,I would leave it to your judgement to whether to add co2 or ferts.
> 
> Barr Report - Non CO2 methods


The above link refers to some ferts, very light topping off ferts.
Some clarification: this is for non CO2/Excel enrichment.

Some folks also use non CO2 methods without soil, nutrient rich base.
Then you will need more ferts.

In general, you can get away with only fish food/waste for ferts for some plants, but the tank will do better and you will have better successes with more species and with the species already present if you top off a tad each week.

Rather than using a test kit, use the plants, as they slow in growth or have signs of low nutrients, add just a small amount.

After a few times, you'll know how much to add to relieve the nutrient stress.
This will help better balance the tank.

Regards, 
Tom Barr


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## plantbrain (Dec 15, 2003)

CO2 and low light is a great combination, easy to achieve good growth, easy to export nutrients/water changes etc.

Excellent growth and color, but not super fast so that you must prune weekly, now you only might prune 2-4 weeks.

Algae and other balancing it also much easier and less intense.
CO2 levels are easier to achieve and so on............

You can do more nutrient dosing methods also.
Substrate ferts alone for the most part can be done much better with this method vs high light.
Just add traces/K+/GH.

But you can still do pure water column dosing with the same success also with low light/CO2.

It's a myth that more light is better and that low light tanks do not gain any benefit from CO2.

They gain the same types of advantages that a high light tank does, it's only mandatory for the higher light systems to have CO2, but way too many folks see that and assume, erronously, that to mean that low light tanks should not have CO2, that's rubbish.

Many scared of CO2 will go that way.
Many that want to have a nice CO2 enriched tank assume that more light will mean better colors and better growth and get one of those nice scapes they see.

Again, a myth.

Most of the older nice scapes seen are low light tanks with CO2.
Most aquatic plants are low light plants.

If you want the lower light tanks to grow better, add CO2, water changes and ferts, you'll be very surprised.

This maximizes the light energy for the plants.
This way the *only thing holding the growth back is the lighting*.

Light is controllable, much more so than CO2 and nutrients.
It is also the largest cost per unit time(electric bill) and often the largest cost in the initial set up.

It is also the main driver of energy input and algae growth rates as well.
So it makes the best sense to limit light, rather than CO2 and nutrients if you seek a balance and good management.

CO2 limitation is slight when you lower the lighting, so is algae growth, that's why the non CO2 method works well also.




Regards, 
Tom Barr


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## Naja002 (Oct 12, 2005)

> This way the only thing holding the growth back is the lighting.


Bingo! And Thank You.

I currently have a 10g Plant only tank that is lit through a *Cracked* Blind--Not Open, just Cracked. I have a 1*gal.* DIY C02 jug that feeds that tank via a DIY Internal Vortex Reactor. I dose it lightly once/wk, and *Was* doing 50% WCs every 2-3wks.

Growth is slow and not stunning, but certainly acceptable. Its just a grow out tank.

Its Plant only and C02 is max. The flow through the reactor is -152gph, but the majority of the tank is pretty stagnant--( there is a sponge at the bottom of the reactor).

Algae is zero. My other tanks are between 2-3 w/gal., with C02 or Excel, and I dose once/wk. I rarely have any algae issues. Sometimes GSA, but I add P and it goes away.


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## distrbd (Feb 17, 2006)

plantbrain said:


> CO2 and low light is a great combination, easy to achieve good growth, easy to export nutrients/water changes etc.
> 
> Excellent growth and color, but not super fast so that you must prune weekly, now you only might prune 2-4 weeks.
> 
> ...


Thanks Tom to clarify it for me. now I Get it and I was wrong thinking and advising others not to use co2 in low light tanks.My bigger mistake was that I equated low light=low maintenance.The reason I have a low light tank is to keep it low in in every aspect so I can concentrate most of my efforts in to the up keep of my so called hi tech tank.but I realize that some my want a low light tank but a faster plant growth.


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## plantbrain (Dec 15, 2003)

I think that division between non CO2 and CO2 is large and a great sourece of confusion for folks in the plant tank hobby.

I think I'm the only person to date to reconcile the duifferences between each method and why they both work. Folks use to say it was "a mystery". Lotta good that does

It's not an easy thing to understand.

Lower light does = lower mainteance
There is certainly a relationship there.

CO2 users should note this and brand it into their brains.
I hear a lot of crying and whining about the fast growth, not being able to keep with pruning etc, but they still do not want to give up their high light.

Lulled into the myth that all their fav plants are high light mandatory plants.
Or that they must have the highest light to achieve the best colors.

Onm the other end, many lower light folks tend to be no/low tech folks not interested in CO2, so they say you don't need CO2 additions, which is true, but they make the mistake by suggesting that CO2 will not greatly help plant growth rates at lower light.

So both sides are guilty.
But, the way around this is to have both groups try the other's method and follow the routine carefully and most will be pleasantly surprised!




Regards, 
Tom Barr


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## sleepswithdafishez (May 23, 2013)

magicmagni said:


> Wow I don't remember that part, but I know he does go into a dosing routine in that article as well for low light/ no Co2. I think some kind of dosing is helpful just not as much.
> 
> Low light planted tank with Co2. I have had awesome results myself. I think the best planted tanks I did were low light with Co2. Plants grow slower so your arrangments stay in place the way you want them for longer (although it takes longer to grow in) and there is a lot more forgiveness when it comes to dosing, meaning that you can get away with a lot more and not get an algea bloom/ stunt plants.
> 
> ...


Just stumbled upon this thread ,and was wondering - what happens to the excess Co2 (you might eventually add due to DIY Co2 fluctuations),the one which isn't consumed by plants due to the low light ,which implies lower Co2 demand?


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## sleepswithdafishez (May 23, 2013)

plantbrain said:


> I think that division between non CO2 and CO2 is large and a great sourece of confusion for folks in the plant tank hobby.
> 
> I think I'm the only person to date to reconcile the differences between each method and why they both work. Folks use to say it was "a mystery". Lotta good that does
> 
> ...


From what I understood from the non Co2 method:

low light - no Co2 - overfertilisation = better(yet slower) plant growth ,less or no algae
high light - no Co2 - overfertilisation = stumbled plants ,algae
high light - diy Co2 - overfertilisation = algae ,most of the time ,due to Co2 fluctuations

what happens in this case? :
low light - diy Co2 - overfertilisation ?

- algae ,due to Co2 not being stable? (going high or low ,but always enough for the plants)
or
-better plant growth ,as long as they have enough CO2(going high or low ,but always enough for the plants)

What happens to the Co2 -that is not absorbed by the plants ,which are limited by low light?Does that lead to algae growth ,cause But the if the diy Co2 is added ,and it's always going up and down ,yet never enough for all the plants (or algae),does that still benefit algae?or is it still consumed by the plants ,bringing a rather small growth improvement?


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## plantbrain (Dec 15, 2003)

hixy said:


> hello folks is it worth using co2 in a low light aquarium
> 
> thanks hixy


http://www.tropica.com/en/tropica-abc/basic-knowledge/co2-and-light.aspx

Tropica shows that you get 3-4x more growth even at low light, this is also easier to trim, garden since the rates are slow, but you still have a lot of lush growth. Their conclusion is similar also, use CO2 and low to moderate light. 

The moderate light they use was about 90 umols, so that's pretty close to high light, 25 is a bit on the very low side, that's what they used for the low light value. I've just converted from lux and know their light source(so I could do the conversion).

The other issue is you can grow MANY species together with CO2 enrichment, not so with non CO2, that's one of the trade offs. You can still grow a few, but........many will not survive over time with non CO2/non carbon enrichment.


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## sleepswithdafishez (May 23, 2013)

plantbrain said:


> http://www.tropica.com/en/tropica-abc/basic-knowledge/co2-and-light.aspx
> 
> Tropica shows that you get 3-4x more growth even at low light, this is also easier to trim, garden since the rates are slow, but you still have a lot of lush growth. Their conclusion is similar also, use CO2 and low to moderate light.
> 
> ...


so i can use diy co2 as long as i don't OVERDO it ,in a low light with plenty nutrients..


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## Jeff5614 (Dec 29, 2005)

sleepswithdafishez said:


> so i can use diy co2 as long as i don't OVERDO it ,in a low light with plenty nutrients..


I might be reading what you're saying incorrectly, but there's not really any overdoing it with CO2 unless you're gassing your fauna. Unless, of course, you're one who agrees that the lower pH levels caused by higher CO2 levels inhibit the functioning of your biofilter, a topic I am unsure of. 

Your plants will require less CO2 in a lower light environment but the idea is to have a nonlimiting amount of carbon, just as with any other nutrient. The best thing I ever did in my tank was going from 80 to 45 PAR at the substrate.


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## sleepswithdafishez (May 23, 2013)

Let's pretend that DIY CO2 has these levels:
not enough
a bit better
good
Optimal pinpoint
Overkill

What I mean is ,that I can always add CO2 to the tank.....and it can fluctuate between "a bit better" and "good" .....but Never Ever from "not enough" ,to "Optimal pinpoint level" or "Overkill" ,so it kills fish.

In conclusion ,if the Co2 is really really low-"not enough" ,the plants will say ....hey ,we need more Rubisco,why don't we make some?

And while they're at it ,algae will say...let's party!

Then ,the Co2 suddenly increases ,to "good" or even "optimal pinpoint"....the plants will say : Hey ,why don't we ditch that extra Rubisco ,we don't need it anymore....

And while they're at it ,algae will say "party time!" ,once more...

Did I nail it right? http://www.barrreport.com/showthread.php/3085-Rubisco


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## sleepswithdafishez (May 23, 2013)

Also explained here: http://fins.actwin.com/aquatic-plants/month.200701/msg00026.html


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