# C02 24/7?



## Vohlk (Apr 8, 2016)

Large pH swings. 2 hours might not be a lot, but over say 8 hours of no light you might be looking at a pretty low pH

Sent from my SM-N900V using Tapatalk


----------



## bacon5 (Jul 25, 2011)

I dont know why you would want to dose the CO2 when the lights are off, since the plants dont use it during cellular respiration which occurs at night. At least I think that is how it works


----------



## Darkblade48 (Jan 4, 2008)

bacon5 said:


> I dont know why you would want to dose the CO2 when the lights are off, since the plants dont use it during cellular respiration which occurs at night. At least I think that is how it works


To be more correct, cellular respiration occurs at all times of the day.

Photosynthesis only occurs in the presence of light. CO2 is only used during photosynthesis


----------



## bacon5 (Jul 25, 2011)

Darkblade48 said:


> To be more correct, cellular respiration occurs at all times of the day.
> 
> Photosynthesis only occurs in the presence of light. CO2 is only used during photosynthesis


Thanks for that correction :smile2:!


----------



## Hoppy (Dec 24, 2005)

The most obvious reason for running CO2 24 hours a day is to be able to set the bubble rate and forget it. Another reason is to not have to be concerned about how long it takes to build up the concentration of CO2 in the tank every day. You can run CO2 continuously if the amount you are adding to the water is low enough that the reduced usage of CO2 by the plants at night doesn't raise the amount in the water above what the fish can live with. I'm sure if you use only 10 ppm of CO2 you can run it continuously. And, if you use 40 ppm you can't run it continuously. And, yes, of course it wastes CO2 to run it at night.


----------



## Jabolko (Jul 18, 2016)

bacon5 said:


> I dont know why you would want to dose the CO2 when the lights are off


More stable PH. :smile2:


----------



## Kensho (Oct 24, 2012)

I agree it would waste some C02, but over all my will be more stable. Instead of blasting a high bbl count during lights-on, and zero while they are offs.


----------



## mistergreen (Dec 9, 2006)

there's nothing wrong with it. Shoot for something like 1 bubble / 30 seconds, depending on how large your aquarium is.
You'd want it to build up over night to something like 25-30ppm before the lights turn on. No need to go higher than this.

I wonder if it's a waste.

CO2 24/7
1/30 sec = .033*60*60*24 = 2880 bubble

CO2 8 hours
3/sec = 3*60*60*8 = 86400 bubbles

just musing


----------



## Hoppy (Dec 24, 2005)

mistergreen said:


> there's nothing wrong with it. Shoot for something like 1 bubble / 30 seconds, depending on how large your aquarium is.
> You'd want it to build up over night to something like 25-30ppm before the lights turn on. No need to go higher than this.
> 
> I wonder if it's a waste.
> ...


I know you have done a lot of tinkering with CO2 measuring over the past 2 years or so. Did you ever figure out how fast the CO2 dissolved in an aquarium will last before it drops down well below 10 ppm? Of course it depends on how much you have to start with, so assume you start at 20-30 ppm.

I'm asking because what you posted above hints that the depletion will not be so fast that you need to keep adding it at a high rate throughout the photoperiod.


----------



## mistergreen (Dec 9, 2006)

Hoppy said:


> I know you have done a lot of tinkering with CO2 measuring over the past 2 years or so. Did you ever figure out how fast the CO2 dissolved in an aquarium will last before it drops down well below 10 ppm? Of course it depends on how much you have to start with, so assume you start at 20-30 ppm.
> 
> I'm asking because what you posted above hints that the depletion will not be so fast that you need to keep adding it at a high rate throughout the photoperiod.


The rate in with CO2 leaves the aquarium depends on the surface area which also includes the surface turbulence. It also depends of the temperature. It leaves really quick in a 75G tank (30 mins) and slower in a 10G with a cover (hours). So there are lots of variables so leaving CO2 on 24/7 might not be a waste. It could save CO2.

I see that heavily planted tanks would consume about 10ppm in a slow passive system within the photoperiod. I don't think I can tell in high rate CO2 injection.


----------



## mrfiock (Nov 15, 2015)

I leave my co2 at 1 bps in my 20L and have for well over a year. I keep a few oxygen-demanding species, including hillstream loaches, and they seem to do fine with the overnight co2. Make sure there's plenty of surface agitation for gas exchange and it should be fine.


----------



## IntotheWRX (May 13, 2016)

Kensho said:


> In the past I have run my C02 for 2 hours before the lights come on and shut off with they go out. Is there a down side to just having the C02 (slower release rate) on 24/7?


i run 1 bbps on my 10 gal 24/7. mainly because I dont have a way to turn it on and off everyday so i leave it on. everything is fine. but theoretically better to turn off at night.


----------



## mistergreen (Dec 9, 2006)

mrfiock said:


> I leave my co2 at 1 bps in my 20L and have for well over a year. I keep a few oxygen-demanding species, including hillstream loaches, and they seem to do fine with the overnight co2. Make sure there's plenty of surface agitation for gas exchange and it should be fine.





IntotheWRX said:


> i run 1 bbps on my 10 gal 24/7. mainly because I dont have a way to turn it on and off everyday so i leave it on. everything is fine. but theoretically better to turn off at night.


Do you guys know how much CO2 (ppm) is in your tank before the lights turn on?


----------



## Clinton Parsons (Apr 11, 2016)

When you have a medium to largish tank, add a sump, add powerheads, add heat from those pumps and lights, you really run through co2 way faster than you thought you would. Keeping the pH stable 24/7 with a controller isn't really worth it versus keeping it stable with a controller during the photoperiod only. I have noticed no difference, other than racing through co2 when I do not try to conserve it.


----------



## mrfiock (Nov 15, 2015)

mistergreen said:


> Do you guys know how much CO2 (ppm) is in your tank before the lights turn on?




My drop checker would have me believe that it's around (or above) 60 ppm before lights on and hovers around 30 ppm all day.


----------



## mistergreen (Dec 9, 2006)

mrfiock said:


> My drop checker would have me believe that it's around (or above) 60 ppm before lights on and hovers around 30 ppm all day.


cool. You can definitely cut down to 1bps/ 2 seconds.

Co2/24/7
1bubble/sec = 1*60*60*24 = 86400

this is exactly the same 3bps for 8 hours. Interesting huh?
3bps = 3*60*60*8 = 86400


----------



## mrfiock (Nov 15, 2015)

mistergreen said:


> cool. You can definitely cut down to 1bps/ 2 seconds.
> 
> Co2/24/7
> 1bubble/sec = 1*60*60*24 = 86400
> ...




Used to be at 1/2 bps, my plants don't stay red, get stringy, and grow algae. Also, 3 bps * 8 hrs doesn't equal 1 bps * 24 hrs in concentration. The water would be way more saturated with co2 than necessary. My water stays at or above 30 ppm. I've found this to be optimal and would be a waste of co2 to raise it. Also, 3bps would probably kill my fish.


----------



## mistergreen (Dec 9, 2006)

mrfiock said:


> Used to be at 1/2 bps, my plants don't stay red, get stringy, and grow algae.


I personally would lower the PAR of the lights to find balance rather than adding too much CO2. I've gone through that route 



mrfiock said:


> Also, 3 bps * 8 hrs doesn't equal 1 bps * 24 hrs in concentration. The water would be way more saturated with co2 than necessary.


The 3bps * 8 hours is only hypothetical. It's depends on the tank to reach 30ppm for 8 hours.


----------



## IntotheWRX (May 13, 2016)

mistergreen said:


> Do you guys know how much CO2 (ppm) is in your tank before the lights turn on?


nope, i dont measure ppm. I measure by looking at the plants and animals and bubbles.


----------



## mrfiock (Nov 15, 2015)

mistergreen said:


> I personally would lower the PAR of the lights to find balance rather than adding too much CO2. I've gone through that route
> 
> 
> 
> The 3bps * 8 hours is only hypothetical. It's depends on the tank to reach 30ppm for 8 hours.




Lol, already lowed the PAR, if I lower it more then my plants won't grow. Like you said, it depends on the tank and mine is running quite optimally as it is.


----------



## Kensho (Oct 24, 2012)

I believe the surface area of my 21x21x21 cube would gas quite a bit of C02.


----------



## IUnknown (Feb 5, 2003)

From what I've read recently, Co2 is not just for plants. It also sustains the nitrifying bacteria colonies. I've changed mine to stay on all the time.

http://www.plantedtank.net/forums/2...nt-24-7-co2-nitrifying-bacteria-colonies.html


----------



## mistergreen (Dec 9, 2006)

IUnknown said:


> From what I've read recently, Co2 is not just for plants. It also sustains the nitrifying bacteria colonies. I've changed mine to stay on all the time.
> 
> http://www.plantedtank.net/forums/2...nt-24-7-co2-nitrifying-bacteria-colonies.html


Nitrifying bacteria is aerobic I think. They need O2 more than anything.


----------



## mrfiock (Nov 15, 2015)

mistergreen said:


> Nitrifying bacteria is aerobic I think. They need O2 more than anything.




Yep. Denitrifying bacteria are the anaerobic ones. They turn nitrate into nitrogen gas.


----------



## Kensho (Oct 24, 2012)

@mrfiock I agree - I am starting with LOW everything (fertz, Light C02) and slowly bring tweak each. I am going to stay away from 'needy' flora and fauna this go round. I'll start 24/7 and see how it goes.


----------



## Bobbybills (Nov 30, 2015)

If a solenoid is used, why would the bubble count have to change? Just use an on/off timer and each morning when it turns on the solenoid opens and whatever count is set is ready to go. At night, the timer releases the solenoid and the CO2 flow stops.

I have tried on all the time, on during the day, and controlled by a Milwaukee PH controller. When running 24/7 the PH never drops below 6.4 at night. With the CO2 only on during the day, the PH climbs to 6.9 maybe 7 as the tank degases at night. Just my experience.


----------

