# Who turns off co2 and who does not at night?



## Aqua99 (Jan 6, 2017)

Each of my CO2 systems runs on its own timer (Wemo Smart Plug). Each one starts CO2 60-90min before the light timers and ends 60-90 min before lights out.

No sense in wasting CO2 all night while not being used. If I ran mine all night at the same rate as I do with the lights on and zero plant useage, I'd only assume my fish would not survive. Even if I could supply a lower rate at night it still sounds like a waste of CO2 as my plants aren't using it.

If you were really bent on injecting two different rates (not that I could see a viable reason to), you could just swap your selonoid for one with 2 outputs that alternate open/closed (4-way, 4-port, and block off the shared exhaust I believe). Run one output to a needle valve set to your day rate and the other output to a needle valve set to your night rate.

I think the only acceptable CO2 to run 24/7 is the DIY yeast setups that only inject marginal levels of CO2.


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## sfshrimp (May 24, 2016)

clownplanted said:


> As the tittle says who of you turn off your co2 at night and who does not? For those that do turn off at night did you lose fish due to co2 running at night? For those that leave it on is it because you do not like the water parameter fluctuation? I installed my first co2 presurized system today on my 60 gallon heavily planted tank. I am using a Fluval 206 dedicated just for the co2 and using a Sera Flore Active CO2 Reactor. I was like a kid at christmas after it was installed. That reactor is awesome. I immediately started seeing plant pearling and all my fish are good to go running 3bps. With the reactor its awesome not seeing any bubbles coming out. But I am just trying to get a feel for if I should keep it running at night or not.
> 
> On another note I think the best thing would be to turn down the co2 but not completely shut off. In the car world of things you know how a remote bottle opener can open your Nitrous bottle. Why is there not something similar that can say turn down the co2 from maybe 3bps to 1.5bps. It would of course take tuning but just think that would be the best of both worlds. What are your thoughts? I know as far as reliability it would have to be something that would not fail and say turn all the way up the co2. Is there anything out there like that?


What you say "night" do you mean the lights are turned off in the tank? If so, you are wasting c02 and maybe even endangering your fish if you don't have a decent KH.


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## Haejin (Feb 13, 2017)

I didnt off the CO2 pump at night. It works 24 hour a day because im using diy CO2 yeast pump and doesnt lose fish at all

Sent from my GT-N7100 using Tapatalk


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## RobnSonji (Oct 6, 2013)

I turn mine off.

My water tests at GH 10 and KH 5. It tries REALLY hard to stay at a ph of 8.

I can set my co2 at a bubble rate wayyyy faster than can be counted and it will drop my ph to 7.4 during the course of a day.
Id be afraid to allow it to inject at that rate at night. 
ph bounces right back to 8 during the night.


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## thejoe (May 23, 2013)

Takashi Amano never ran C02 at night (when lights are off) in one of his interviews he stated "it is rude to run C02 at night" that always brings a smile to my face.


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## ehorn (Feb 16, 2013)

For me (pressurized setup): CO2 goes on 1 hour before photo period starts and goes off 1 hour before photo period ends. The ideal is to get ppm up to idealized levels as photosynthesis begins and keep it there during the photo period.

Air stone goes on 30 minutes after lights out and goes off 4 hours before CO2 goes back on. The goal being to off gas CO2 and increase O2 for respiration period.

Aquarium Life




clownplanted said:


> On another note I think the best thing would be to turn down the co2 but not completely shut off.


Why do you think that?

peace,


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## RobnSonji (Oct 6, 2013)

ehorn said:


> For me (pressurized setup): CO2 goes on 1 hour before photo period starts and goes off 1 hour before photo period ends. The ideal is to get ppm up to idealized levels as photosynthesis begins and keep it there during the photo period.
> 
> Air stone goes on 30 minutes after lights out and goes off 4 hours before CO2 goes back on. The goal being to off gas CO2 and increase O2 for respiration period.
> 
> ...



I THINK the idea is to avoid the ph swings caused by the co2 ?


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## ehorn (Feb 16, 2013)

RobnSonji said:


> I THINK the idea is to avoid the ph swings caused by the co2 ?


Lots of good info out there on this topic. 

It is rapid changes to KH/buffering systems which pose more harmful effect (i.e. pH change via salts are bad). 

CO2 is not a salt. Of course you can gas your fish, but this is due to excess CO2, and not pH (although it is affected).

The pros shut off CO2 at night. I see no reason to contest their experience and wisdom.

peace,


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## clownplanted (Mar 3, 2017)

ehorn said:


> For me (pressurized setup): CO2 goes on 1 hour before photo period starts and goes off 1 hour before photo period ends. The ideal is to get ppm up to idealized levels as photosynthesis begins and keep it there during the photo period.
> 
> Air stone goes on 30 minutes after lights out and goes off 4 hours before CO2 goes back on. The goal being to off gas CO2 and increase O2 for respiration period.
> 
> ...


Yes to avoid the PH swings.


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## Nlewis (Dec 1, 2015)

clownplanted said:


> Yes to avoid the PH swings.


There is no point in leaving it running at night, all you're doing is wasting co2 and risking killing all your fish. The ph swing caused by co2 if you have it dialed in should be about a 1 point drop and the fish will be fine with that as it takes some time to degas. Ph swing that you want to avoid are those that happen rapidly like when you do a water change or when acclimating new fish.


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## Aqua99 (Jan 6, 2017)

ehorn said:


> ...
> It is rapid changes to KH/buffering systems which pose more harmful effect (i.e. pH change via salts are bad).
> ...


Totally agree with this^^^

My fish and somewhat sensitive shrimp could care less about a one point pH swing. If the GH,KH, or TDS drastically bounces around... they're either floating or laying lifeless on the bottom.


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## nikohak (Oct 21, 2016)

I think there is a difference in trying to keep low (5-10ppm) or high (+25 ppm) CO2 in the tank and injecting CO2 from canister.

When aiming for low CO2 and not turning the gas off for night:
- the risk of gassing your fish is small. Maybe smaller than if you start fiddling with timers and higher bps.
- the excess gas consumption is quite small. At least in small/medium sized tanks.
- the water parameter fluctuations caused by a little extra CO2 are quite mild. For those who think it makes a difference.

When aiming for high and not turning the gas off for night:
- you need to almost be a magician and have everything always work 100% as planned to not gas the fish
- it would be cheaper to buy solenoid and stuff, than consume the gas so much.


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## klibs (May 1, 2014)

Aqua99 said:


> Each of my CO2 systems runs on its own timer (Wemo Smart Plug). Each one starts CO2 60-90min before the light timers and ends 60-90 min before lights out.


exactly what i do


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## IntotheWRX (May 13, 2016)

clownplanted said:


> As the tittle says who of you turn off your co2 at night and who does not? For those that do turn off at night did you lose fish due to co2 running at night? For those that leave it on is it because you do not like the water parameter fluctuation? I installed my first co2 presurized system today on my 60 gallon heavily planted tank. I am using a Fluval 206 dedicated just for the co2 and using a Sera Flore Active CO2 Reactor. I was like a kid at christmas after it was installed. That reactor is awesome. I immediately started seeing plant pearling and all my fish are good to go running 3bps. With the reactor its awesome not seeing any bubbles coming out. But I am just trying to get a feel for if I should keep it running at night or not.
> 
> On another note I think the best thing would be to turn down the co2 but not completely shut off. In the car world of things you know how a remote bottle opener can open your Nitrous bottle. Why is there not something similar that can say turn down the co2 from maybe 3bps to 1.5bps. It would of course take tuning but just think that would be the best of both worlds. What are your thoughts? I know as far as reliability it would have to be something that would not fail and say turn all the way up the co2. Is there anything out there like that?


It is BETTER to turn off the co2 when the lights turn off. When the lights are turned off, all the plants go to sleep. They will not be eating up co2. Save the co2 for when the lights turn back on. $5 timer can help you with this.

Although, you can run co2 24/7 for those who cant turn it on/off with a switch. It works just fine.


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## clownplanted (Mar 3, 2017)

Funken_A said:


> I have mine going 24/7 I found I could maintain better PH stability/ CO2 saturation consistensy with my kh somewhere between 6 - 9. I have the main valve running 24/7 and I fire on the solenoid during my high light period which increases BPS.
> 
> I like to maintain a ph between 6.8 and 7.2 on average and still maintain > 20 and < 40 ppm CO2 . When I run CO2 and turn it off my ph swings are more dramatic.. I also do not want to dive down into lower pH levels as I house nerlite and rabbit snails. Hoping neutral PH reduces the stress on them


Love your setup. Very nice.


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## DigityDog70 (Jan 20, 2017)

On a timer, 30 mins before and after the lights turn off. One less thing to worry about.


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## MCFC (Feb 12, 2017)

Funken_A said:


> I have mine going 24/7 I found I could maintain better PH stability/ CO2 saturation consistensy with my kh somewhere between 6 - 9. I have the main valve running 24/7 and I fire on the solenoid during my high light period which increases BPS.


Huh? Doesn't the solenoid just control co2 on/off? So if your "main valve" is running but the solenoid isn't, shouldn't your bpm be 0?


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## lksdrinker (Feb 12, 2014)

I'm always amazed when this kind of question pops up. Even more amazed by the answers some give and the reasoning behind it lol. In my opinion; keeping the co2 on at night is like dosing ferts in a tank full of nothing but silk and plastic plants! Sure it didnt kill the fake plants......but its not providing any benefit except to whomever you pay for the gas!


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## RobnSonji (Oct 6, 2013)

lksdrinker said:


> I'm always amazed when this kind of question pops up. Even more amazed by the answers some give and the reasoning behind it lol. In my opinion; keeping the co2 on at night is like dosing ferts in a tank full of nothing but silk and plastic plants! Sure it didnt kill the fake plants......but its not providing any benefit except to whomever you pay for the gas!



I think you're missing the point.

I dont do this (mine is off at night) but I can see why someone would.

By allowing the co2 to run at night....or a hybrid setup like Funken....you are maintaining a stable ph along with getting a jump on co2 demand when the lights comes on.
Some people have algae problems and suspect that the daily ph fluctuations caused by co2 on/off is part of the problem.

Its all about stable ...consistent water parameters. GH/KH/PH staying the same 24/7 and the co2 level changing accordingly to maintain the others

My GH is 10....KH 5. 
At night(co2 off) my PH is 8.0 to 8.1
Daytime(co2 on) my PH runs 7.3 to 7.4

Are the daily PH swings harmful to fish or plants? Im not sure but I am currently growing a lot of algae lol


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## lksdrinker (Feb 12, 2014)

RobnSonji said:


> I think you're missing the point.
> 
> I dont do this (mine is off at night) but I can see why someone would.
> 
> ...



I'm not missing the point at all. By allowing the co2 to run at night all you're doing is running co2 at night and potentially you can gas your fish to death. You can "get a jump" on the co2 by having it turn on an hour or so before the lights and thats about all you'll really need. Plants simply cannot use the co2 without light. Photosynthesis needs light to happen. The all you can eat buffet doesn't load up the food while they're closed so they can get a jump on the lunch rush. If it cant physically be used at a certain time there is little reason to do it! The amount of co2 you're injecting is not going to change your kh or gh; and while yes it does alter the ph reading, for some reason that doesnt seem to negatively affect fish the way "natural" ph changes can. If you're keeping the ph of your tank stable 24/7 in a planted tank with co2 injection....then you're not using the co2 correctly. I promise you algae is not caused by fluctuating ph levels based solely on co2 injection and certainly isnt caused by a lack of co2 during the overnight hours. Perhaps some have mistaken the fact that once they got good growth from their plants they see less algae; but that doenst mean keeping the co2 on 24/7 is the answer.


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## lksdrinker (Feb 12, 2014)

Funken_A said:


> Reading comprehension does help some. PH control !!!!!
> 
> I've tried numerous times to control my CO2 and turn it off at night and maintain a reasonable PH swing... I get way tighter control running 24/7
> 
> ...




Reading comprehension certainly does help. I read it. I comprehended what was written. That doesnt make it correct! I too see a drop in ph while the co2 is on....as does everyone who injects co2. The addition of crushed coral is not going to negate that (its a buffer that will naturally allows/causes the ph to rise). The addition of co2 is going to cause the ph to drop (if you're buffering with crushed coral then the co2 will cause the ph to drop from wherever it is after the coral has buffered the water). Ideally a drop of roughly 1 ph point is expected when you inject co2 and although it seems counter-intuitive most species dont seem to be negatively impacted by this ph swing. 

I see no benefit in keeping co2 saturation at X level when there is no light, no photosynthesis and no co2 being used by the plants.


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## natemcnutty (May 26, 2016)

I think you might be missing a couple of things. Adding crushed coral will raise both your pH and carbonate hardness (KH). This means you have to inject even more CO2 to achieve the same levels at a lower KH.

I think @lksdrinker is trying to help you realize that you could achieve the same result leaving your KH alone just decreasing your CO2 infection rate. 

I'm not going to state this as fact, but I'm fairly certain that for snails pH brought below 7 due to CO2 is not the same as water with a regular pH below 7. I have plenty of snails (nerite, mystery, mini-ramshorn) that have no issues with me dropping from 7.4 to 6.7ish for 10 hours every day, but I lost plenty of mysteries in water that was around 6.6 during college when I didn't know better. 

Make sure you have enough calcium (check GH) and just enough KH to prevent risk of large swings (2-4 dKH is fine). I'd stop messing with your pH/MB and just inject less CO2 if you don't like the pH swing. 

Sent from my Nexus+6 using Tapatalk


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## lksdrinker (Feb 12, 2014)

Funken_A said:


> OK if you say so. You really need to improve those reading comprehension skills You pretty much reiterated everything I said about crushed coral PH levels and CO2 accept you still refuse to understand PH stability is the goal.
> 
> I have nice stable PH levels in the middle of the night at the beginning of light cycle, in the middle of the light cycle and at the end of the light cycle. No real swings and no PH controller. Also this system helps make up for the imperfections of metering valves which are pain in the ass to dial that accurately
> 
> ...


 I refuse to understand ph stability is the goal? How would anyone know what your particular goal might be? I think you're misunderstanding how some of this works. Whether or not you use crushed coral you will see the ph drop when you inject co2 and it will rise up again when/if you stop injecting. The crushed coral will buffer the water and allow the ph to rise. The injected co2 will still cause it to drop....just from that now elevated starting point. So the "reality of it is" that you (and everyone else comparatively) will see co2 rise up (to 7 in your case) when the co2 is off and drop down (to the 6s in your case) when the co2 is on; because thats exactly what happens when you add co2 with or without a buffer like crushed coral.

If you're increasing the co2 level during your high light period then the ph should be dropping. Otherwise you're likely not increasing as much as you think. One is a direct correlation to the other. If the ph isn't moving then the co2 injection isn't changing.

Are you seeking stable ph levels because you've experienced problems due to fluctuating ph levels solely from injecting co2? Plenty of us in this hobby keep sensitive species that are known to "want" certain ph levels. Many have known those species to not do well, or die, when brought from one hobbyist to another who happen to have different water sources. However, these same sensitive species dont seem to be harmed by ph fluctuations when its caused by co2 injection. Wish I understood why exactly. 

Just because this method happens to work for you does not mean the reason is what you expect it to be.


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## RobnSonji (Oct 6, 2013)

lksdrinker said:


> I refuse to understand ph stability is the goal? *How would anyone know what your particular goal might be?*
> 
> *If you're increasing the co2 level during your high light period then the ph should be dropping.*
> 
> ...


Its been stated multiple times in this thread....and some understood that from the beginning.

Not necessarily true if you increase co2 to meet a higher consumption rate. If the plants are consuming it at or near the same rate you're injecting it your ph would remain the same..... i.e. like a ph controller does

This statement could be applied to a Kazillion things in life. Including your method.


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## H2O Life (Dec 31, 2016)

To prevent ph fluctuations, I used to use a ph monitoring system that hooked up to the pressurized co2...automatic on/off once I set the desired ph level. Ideal when I was breeding discus but I found it not very useful when trying to increase the co2 level for the plants.


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## Trippytrix (Jun 24, 2018)

I do not turn off my co2 in my tanks. I use silicon tubing as well for my co2 system. I'm also using the Ista brand for my co2 tank. I run a 3.5g, 10g, and 75g fully planted iwagumi style tanks. Hob filter for my 3.5g, a nano canister filter with lily pipes for my 10g, and a canister filter with lily pipes for my 75g.

The 3.5g is stocked with dwarf baby tears, 3 amano shrimps, 10 CRS, and 5 microrasbora galaxy. I used ADA additives when I first set up my aquarium. I'm also dosing the aquarium with Aquavitro products. It's been 2 years and everything is balanced and nothing bad has happened with the aquarium.

The 10g is stocked with dwarf baby tears, dwarf hairgrass, cryptocoryne, 15 ember tetras, i don't know how many CRS is in there, 5 amano shrimps, and 3 otocinclus. The same products (ADA additives and Aquavitro dosing products) used like the one for the 3.5g. 4 years and it's still going strong.

The 75g is stocked with dwarf hairgrass, amazon swords, rotula (i forgot how to spell it...the one where red hues show on the tip of the plant), a lot of amano shrimp, a lot of CRS, 30 ember tetras, and 10 white cloud minnows. Same products used as well. 4 years strong.

Everything is balanced and constant in my tanks. No fluctuations, no algae and bacteria problems, and no live stock has died due to tank screw ups. I bring the lily pipe close to the surface of the water when the lights are off to give the tank more oxygen and surface agitation. For the 3.5g, I speed up the flow on the hob just a little bit. I also add fishes by small batches and not the full desired number of fishes you want for your tank. I change the water weekly (20%-25% water change) and trim the plants often. For the filters, clean them as instructed for your tank.

Basically, I do not turn off my co2 at night and i use the filters like an airstone to give it more oxygen at night. I know i'm basically wasting co2, but to answer the question of will my fish die or will my tank screw up if I don't turn off my co2 is a false for me. Just be patient when initially setting up a high tech tank. Be patient. Wait for everything to be good before putting in fishes, shrimps, etc in the tank. If you're setting up a pressurized co2 system on a tank that is already stable, start off slow with the co2. For example, 1 bubble for this day then after 2 days 2 bubbles and so on till you reach your desired bubble count that is needed for your aquarium.

Just be patient and eventually all you have to do are water changes, dosing, trimming, and you don't have to check the parameters of your aquarium that often anymore. Let the tank do its work.


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