# CO2 questions



## snyderguy (Feb 9, 2010)

I started a new thread about this because apparently I don't understand all there is to understand about CO2. In another thread, someone said something about how the CO2 needs to be turned off at night but why? I do have a DIY CO2 system which consists of 2 2 liters of pop bottles as well as 110 watts of light. My plants are all healthy and everything but grow either really slowly or not at all. So what is it I'm missing here? I leave the light on for about 12-16 hours a day but another thing I've noticed is that I have algae growing on the leaves of some plants. They most attracted to my red ludwigia but not my amazon swords. I read somewhere that this may be because I don't have enough CO2? Any help would be appreciated. Thanks.


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## MetalHead (Aug 18, 2010)

most people recommend that the CO2 be turned off in the night as the plants are liable to suffocate to death. contrary to popular misconception, plants, like humans, breath O2 to live. the photosynthesis process during the day off sets their CO2 Discharge with the O2 discharge. however, during the night, there is no photosynthesis, there by drastically increasing the CO2 content in the water.

Algae spurts are a sign of lack of 2 things: Light and CO2. i am assuming that the 110watts of lighting is on the 72Gl? thats not sufficient. basis on the plants you have listed, you would need to average a minimum of 3wpg. 72*3=216 watts of light.

Are u dosing your plants with Micro and Macro nutrients?


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## snyderguy (Feb 9, 2010)

I've got all kinds of different plant stuff that I have buried in the sand that I know they run their roots through so I guess I've just got the whole issue of the CO2 being on too much. Would it be better to stop using CO2 for a little bit considering I don't actually have a way to turn it off? As for the light, I really don't have any other way of getting more light but would it be sufficient enough to leave the light on longer than usual -- more like 18 hours?


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## MetalHead (Aug 18, 2010)

as for CO2 i would suggest you invest in a good soloniod valve diffuser hooked into a pressurized CO2 tank.

as for lighting you could redo the hood to house higher watt t5's.


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## snyderguy (Feb 9, 2010)

Neither of those are really an option so I'm going to have to figure something else out... Thanks though


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## TheOldSalt (Jan 28, 2005)

You are getting algae because you are already leaving the lights on for too long. Running the lights on for longer will not really help overcome bad lighting. Do not increase to 18 hours, and instead cut back to 10.


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## Tallonebball (Apr 6, 2009)

Yeah your lights should be on 8 to 10 hours a day. More would only add to your algae problems. 
I would just scrap the C02 system, buy some plant fertilizer (use it at your discretion, you don't have to follow the bottle instructions), and do water changes with mineral water.
And as I told you upgraded lighting would do well if you can ever do that. Maybe even giving your tank some sunlight.


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## snyderguy (Feb 9, 2010)

I looked up some of the symptoms of my plants too. They seem to become glassy and just really weak looking, so I ordered some substrate fertilizer pills that should help. Does it matter what I use between in the ground substrate versus liquid fertilizer?


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## Schwartzy61 (Jan 25, 2010)

snyderguy said:


> I looked up some of the symptoms of my plants too. They seem to become glassy and just really weak looking, so I ordered some substrate fertilizer pills that should help. Does it matter what I use between in the ground substrate versus liquid fertilizer?



I use seachem's flurish line and it comes in the liquid form. Works great. Just keep in mind that plants like hornwort and watersprite absorb their nutrients through their leaves / needles and absorb them very fast. Plants like ruffled swords and anubis get most of their nutrients through the substrate....just look at their root system...much better than watersprite and hornwort dosent have roots haha just an example. So as for ferts...i say it depends on what plants you have. But for now im just using flourish and its awesome


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## snyderguy (Feb 9, 2010)

I'm using the seachem flourish at the moment and it's hard to tell if it's working. I've reduced the lighting hours to about 10 but I am still watching.


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## jones57742 (Sep 8, 2007)

snyderguy said:


> I do have a DIY CO2 system which consists of 2 2 liters of pop bottles as well as 110 watts of light. My plants are all healthy and everything but grow either really slowly or not at all.
> *So what is it I'm missing here? *
> I leave the light on for about 12-16 hours a day but another thing I've noticed is that I have algae growing on the leaves of some plants.


sg:

I am assuming your post refers to your 72 gallon bowfront.

Plant growth is principally composed of lighting, fertilization and CO2.

Your lighting intensity is approximately 1.5 WPG which is sufficient for only low light plants. Increasing the lighting duration will not compensate for a lack of intensity but will cause algae. My lighting duration is typically 8 to 10 hours per day.

Flourish is basically just micronutrients. In order to attain good plant growth you will also need to fertilize with macronutrients. Please refer to Rex Grigg's site. 

Your DIY CO2 is probably producing approximately 10ppm. The typical concentration from atmospheric induction is 2ppm. The folks with pressurized CO2 run 20ppm to 30ppm. 10ppm is plenty adequate for plant growth with appropriate lighting and fertilization but will otherwise cause algae.

TR


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## snyderguy (Feb 9, 2010)

So somehow I need to get more light.. I'll see what I can do.


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## snyderguy (Feb 9, 2010)

Is there really anything I can do to get more light without having to buy a new light fixture?


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## snyderguy (Feb 9, 2010)

Ok so I figured something out and I was able to take 2 smaller fixtures and get a 15W bulb and a 20W bulb so now I have a total of 145W... if it works that way? What do you guys think?


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