# CO2 Injectors at Nightfall



## logan84 (Jul 27, 2011)

Well I finally made my own injector and it brought a tear to my eye when I saw the first burst of bubbles. Now I'm just ridiculously excited to go home from work and see that all of my plants are photosynthesizing and have doubled in growth. Heh. I wish. 

But I was wondering if I should leave the CO2 flowing at night. My tank is a 56 gallon and I'm just using two one-liter bottles with the classic yeast/sugar water set up. So I don't think I'm blowing the water up with CO2 too much. Though I'm reading all kinds of stuff on the internet about some people turn it off so not to suffocate anything and some people leave them on as to avoid pH flux...

What do you think I should do? My fish all seemed happy today - they appeared to have been gasping a little but they all hung out near the plants or wood so I think turning the light on just caught them by surprise this morning and the panting was just from jolting them awake maybe. Plus I don't really think I'm pushing enough CO2 into the water at night to really do any harm... but thoughts?


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## NeonShark666 (Dec 13, 2010)

Putting CO2 into your tank at night does your plants no good. They don't use CO2 until the lights arre turned on. Shutting off your CO2 will allow your ph to rise. How much it rises will depend on your water chamistry. Very soft water can have extreme ph changes when CO2 is turned off. For some fishes, like Tetras, this is no big deal.


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## logan84 (Jul 27, 2011)

NeonShark666 said:


> Putting CO2 into your tank at night does your plants no good. They don't use CO2 until the lights arre turned on. Shutting off your CO2 will allow your ph to rise. How much it rises will depend on your water chamistry. Very soft water can have extreme ph changes when CO2 is turned off. For some fishes, like Tetras, this is no big deal.


Oh for sure - I know that the plants switch to oxygen at night hence not wanting to suffocate anything at night with the CO2. Since it's a home grown kit I made there isn't really a cord to pull at night to shut it down - I'd literally need to just pop a hose off and let the yeast send it's magical CO2 into the atmosphere. Which while not too difficult it's a step I'd like to avoid since I am lazy. So I'm really just trying to figure out really if I HAVE to stop it at night. So far I'm guessing I don't have to... so far


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## DocPoppi (Mar 4, 2011)

If it's a DIY like you say, then it's no big deal. Unless you have a trashcan size sugar/yeast reactor creating as much c02 as an air pump.
You could also put a plastic airline needle valve and dial it down to next to nothing. So to much pressure doesn't build up.


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## pjones (Jun 5, 2011)

I used 2 2 liter bottles with the yeast/suger set up on a 55 gallon, I left it running 24/7 and just turned on the air stone at night to be safe


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## DocPoppi (Mar 4, 2011)

Pjones... That kinda defeats the purpose of the C02.


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## pjones (Jun 5, 2011)

Not at night, plants don't use c02, oxygen gets rid of it at night, my plants thrive doing it this way.


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## DocPoppi (Mar 4, 2011)

Yeah I know the plants don't use it at night, but the chemistry of water allows for only so much molecular bonding. So in therory your saturating, then switching then re-saturating.
But it seems to work for...


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## aquaticsnerd (Jan 29, 2011)

I've been running a DIY CO2 on a 28G for over 6 months now. I basically do the same thing PJones does. The air pump is on a timer that turns on only at night. I see no massive PH swings at all.


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## majerah1 (Oct 29, 2010)

To make it easier to pull a hose,I made a bubblecounter our of a check valve and a syringe I had from refilling my ink.You take the plunger out and shove the check valve up there then add water.Then attach the line from the tank to the top and the one from the bottle of CO2 to the bottom.Use a suction cup to hold it to the tank,and pull the top line at lights out.Its manual but it works fine.

Heres a pic of what Im talikng about.


The check valve has an arrow pointing the direction of the flow of course,and as you can see it points up.The part where the needle screws onto the syringe is the perfect size for the air tubing to fit snug.


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## giddetm (Apr 30, 2011)

Don't forget if you stop the DIY at night and it does not have a way to release the pressure you coulld wake up to a mess.


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## jackspratt (Jul 19, 2011)

Totally agree. Mine thrive this way as well. No need to turn co2 off if your pumping O2 at night.

Here's proof --> Tankscapers


pjones said:


> I used 2 2 liter bottles with the yeast/suger set up on a 55 gallon, I left it running 24/7 and just turned on the air stone at night to be safe


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## DocPoppi (Mar 4, 2011)

Is use DIY system with fine airstone at base of HOB intake, it runs 24/7. HOB creates enough surface turbulence for 02 exchange.
Lots of setup's work just fine.
Logan84 you'll be fine, whichever way you do it.


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## logan84 (Jul 27, 2011)

DocPoppi said:


> Is use DIY system with fine airstone at base of HOB intake, it runs 24/7. HOB creates enough surface turbulence for 02 exchange.
> Lots of setup's work just fine.
> Logan84 you'll be fine, whichever way you do it.



Thanks, Doc! I'm really excited about this all. Can't wait for my plants to actually start showing some enjoyment from the CO2


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## snail (Aug 6, 2010)

I read a study somewhere about rapid ph swings caused by CO2 fluctuations, it said they are for the most part harmless to fish. Ph swings caused by water hardness is quite different and can quickly be fatal because of osmotic shock.


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## James0816 (Jun 19, 2009)

If running DIY CO2...don't even worry about trying to shut it off or disconnecting tubes. It will be more trouble than it worth.

With (2) 1litre bottles on a 56, I doubt you're getting much in there to make a difference anyhow. I would just run airstone at night if you are worried. Best option.


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## jrman83 (Jul 9, 2010)

jackspratt said:


> Totally agree. Mine thrive this way as well. No need to turn co2 off if your pumping O2 at night.


O2 and CO2 are completely different and not respective to each other. In other words, if the CO2 content is too high in your tank it doesn't mean that increasing O2 will keep it from killing your fish.

Air stones are used at night to create a surface disturbance which helps the CO2 be evacuated from your tank.


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## Gizmo (Dec 6, 2010)

jrman83 said:


> Air stones are used at night to create a surface disturbance which helps the CO2 be evacuated from your tank.


+1

That's the system I use on my 10 gallon - CO2 diffusion during the day with a Red Sea Max reactor, turn the reactor off at night and turn a bubbler on. Come to think of it, I might just be able to remove the bubbler now...

DIY CO2 systems are not very effective compared to a system like pressurized CO2, which you REALLY need to look into turning off at night (though, I still don't because I'm a cheapo and won't spend the money on a solenoid). You also can't really "turn off" DIY CO2 unless you turn off its means of diffusion into the water.


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