Stable CO2

Richard40

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Hi what’s the best way to know you have stable CO2?

George farmer mentions to have around one bubble per 50 litres on your bubble counter. I’m finding that the drop checker hasn’t turned like green before the lights come on when I run my CO2 this way. The only way is to turn the bubble counter up, but is this too much now.

CO2 usually comes on at 12 and lights on at 4.

I have had some BBA which suggests unstable CO2 so I’d like to get to the bottom of this and make sure it’s stable so I get good plant growth.
 

ReefLewis

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What type of diffuser do.you have and where abouts is it placed in your system ?

Also, I assumed that it is one bubble per second, yes??

Sent from my SM-G960F using Tapatalk
 

Zeus.

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Hi what’s the best way to know you have stable CO2?

measure the pH preferably with pH meter every 30mins form CO2 on till CO2 off then plot a graph, ideally the graph/pH should be flat/stable from lights on till CO2 off.

If the Drop Checker (DC) turns green two hours after lights on and the pH is stable as above you cracked it.

As to the BPS its very tank and bubble counter dependent. I have a 500l and heres my BPS


Getting a stable [CO2] is hard but its also important to have good flow. Our resident CO2 expert says FLOW is king in a high tech tank and I for one must agree ;)
 
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Water hardness also has a massive effect... The harder the water the harder it is to get it to dissolve into the water , but equally the more stable it seems to be..
I've got hard water and pump the stuff in so fast you don't have a chance at counting the bubbles per second without a high-speed camera.

Getting a stable [CO2] is hard but its also important to have good flow. Our resident CO2 expert says FLOW is king in a high tech tank and I for one must agree

I would also agree with this, high flow and good circulation makes life so much easier...
 

Richard40

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A32C93DF-DC2F-4805-989E-8739FC3647A1.jpeg
Thanks firstly for the replies, it’s a Neo diffuser that I place at the back far right, as my glass outlet pipe is on the right side of the tank.
Yes I meant a bubble per second, as he recommended a bubble per second per 50l. Pic attached.

Regarding flow I have my Oase 600 turned on about half way, I’m worried if I turn it higher the fish will struggle?

I was told to make sure that about an hour before the lights come on the drop checker should turn lime green and stay lime green until switched off about half an hour before lights go off. Lights on are on at 4, CO2 starts at 12 and lights off at 10.

I live in Manchester so the water is very much in the middle regarding hardness.
 

foxfish

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One bubble per second can only ever be an guide line unless you can define the size of the bubble.
Different set ups can vary hugely, how many plants, flow, lighting, interior layout and so many other factors can effect the amount of C02 required.
Use the guide line but except you may have to modifie it to your own needs.
Obviously adjusting C02 levels can be very dangerous for any living inmates and most certainly would be a lot easier without any fish to worry about.
 

Richard40

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I had it lime green on the drop checker before the lights came on with only a moderate flow. Maybe my flow needs to increase. I've seen some BBA which made me think the CO2 wasn't stable in my tank.

I will do the PH checking once I've bought a Hanna PH checker.
 
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It's a common myth that CO2 concentrations must be stable at the start of the photoperiod to the end. Plants do not care. And BBA is not the direct result of "unstable CO2", another myth.
 

Zeus.

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It's a common myth that CO2 concentrations must be stable at the start of the photoperiod to the end

From Start of photo period to end it is best keeping [CO2] stable the reasons are-

A. We understand that Rubisco's job is to capture CO2 molecules and to deliver the molecules to the Calvin Cycle reaction centers. We know that Rubisco is hugely expensive and consumes a lot of resources to produce and to maintain. In low tech tanks, where the CO2 concentration is low there is a much higher density of Rubisco in the leaf because you need more of the protein to capture the small amounts of CO2. In gas injected tanks, the Rubisco density in the leaf is lower.

B. We also know that during Calvin Cycle, the fixing of Carbon involves some intermediate carbohydrate products until the final product is a type of glucose.

So, for item A. we know that when the plant senses that high concentrations of CO2 is available, it responds by reducing the production of expensive Rubisco. When it senses a lower CO2 concentration it must increase Rubisco production, however because this protein is so complicated and heavy, the increased production requires 2-3 weeks in order to change the density in the leaf to match the new gas concentration level. So it is much easier to reduce production than it is to increase production. When increasing gas injection therefore, it hardly takes any time to see an improvement in health. When lowering the concentration, the plant will suffer because it must now ramp up Rubisco production to account for the loss of CO2 availability.

When increasing the light, the plant must reallocate resources from Rubisco production/maintenance in order to deal with the increased radiation. This may entail new pigment production for protection. When the light is reduced, the plant then reallocates the light gathering proteins and can devote them to Rubisco production/maintenance.

So when we mess around with light and gas, we have some degree of predictability.

So plants dont care but the chemical pathway to capture the CO2 molecules does.

If you have some other explanation of why it doesn't need to be stable we will be happy to listen esp if it backed by one of our 'peers' or a scientific paper would be nice also.

Doing posts like

It's a common myth that CO2 concentrations must be stable at the start of the photoperiod to the end. Plants do not care. And BBA is not the direct result of "unstable CO2", another myth.


Does nothing but create myths, esp when you backup the statement with nothing. We will be happy to hear your thoughts/theories why a stable [CO2] isnt require, in the meantime 'The Mysterons will be watching you!'
 

Witcher

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It's a common myth that CO2 concentrations must be stable at the start of the photoperiod to the end. Plants do not care. And BBA is not the direct result of "unstable CO2", another myth.
If CO2 is unstable then we have big chance that plants will start to photorespire and diffuse ammonia - that means loss of nitrogen. If the process is rapid we'll have melting leaves and very likely algae.
 

zozo

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I'm don't call myself an experienced CO² user, in my total aquarium history, i only used 10 litres CO², then I gave up on it. Too much hassle for me.

But break it down with some logic!? And ask the question of "How to determine unstable CO² administering?"

BBA? Or simply count bubbles for a minute and assume it will averagely give the same amount of bubble per minute in a max? 720-minute cycle? Or by looking at the color of the drop checker, that has next to a 2 hour reaction time an indistinguishable green colour palette of greens between pH 6.4 and pH 7. You need an extremely keen eye to see what pH you are at without a colour reference next to it.

The conclusion can only be that it is very relative... :) And most common explanations and statements have some contradictions.

Such as CO² uptake by plants doesn't have an instant on and off switch. By references i read from very experienced (hobby) botanists it seems to work like an engine that needs to warm up and some time to reach the maximum uptake. Then we start an hour before lights on to get to a green DC and we administer a stable amount of BPM. Lights come on and we have X ppm CO². Plants slowly start to respirate need X time to come to a maximum uptake. But the BPM doesn't change, but more CO² is taken up. I never checked but is this is true then this can only result in an X amount of PPM CO² decrease in the water. It actually could be checked with permanent pH measurements. There should be a lower pH at lights on then you would measure at mid-light cycle.

And the logic in this says thus CO² can never be stable like this for the entire light cycle. Fixed CO² administering with a dynamic CO² uptake.

Can a regulator be 100% stable for the entire cycle? Taking temperature rise and fall into account it can not. Thus by counting bubble for 1 minute at 1 time can not give you an absolute correct result for the entire cycle.

Thus unstable CO² is very relative and i have no idea where the threshold is at what point CO² administering is deemed unstable, but it must be significantly noticeable with counting a different amount of bubbles each minute or 2 or 3 i don't know. :) And if this isn't the case, then how would you determine it isn't stable?

Then take a pH controller to regulate CO². Here is often stated that's this is a guarantee for unstable CO² and BBA. If the above statement is true then this absolutely can not be true.

Because the pH controller uses the set pH profile to shut CO² administering on/off. It keeps the CO² PPM stable per 0.1 pH, no matter how dynamic the uptake.

I'm at a loss here to find truth or myth... Maybe there is a bit of both..
 
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zozo

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Another thing to take into account in this story is Low Tech... :) I monitored the pH profile in my low tech for about a year with a permanent pH meter. And it was rock steady pH 6.8 at lights on and slowly rising to pH 8.5 at mid day. Till lights out then drop again.. This was averagely fairly static numbers every single day for the entire year.

Now if that aint unstable CO² i don't know what is.. Does this mean every low tech aquarium should be stacked to the top with BBA or an unsightly amount of algae in general?...

In my personal experience not always..
 

Witcher

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And it was rock steady pH 6.8 at lights on and slowly rising to pH 8.5
I think there is a difference between slowly rising/falling and massive jumps of any parameter within hour or so. Without a doubt tanks are slowly saturated/desaturated by CO2 or oxygen (similar to temperature rising etc.) but it's not a rapid process - and I think rapidness is a key here.
 

zozo

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I think there is a difference between slowly rising/falling and massive jumps of any parameter within hour or so. Without a doubt tanks are slowly saturated/desaturated by CO2 or oxygen (similar to temperature rising etc.) but it's not a rapid process - and I think rapidness is a key here.

Yes indeed, looking at it from a natural point of view. There should be a pH rise and fall slowly over the entire cycle as it would do in nature.

This can only be achieved with a fixed amount of BPM over this cycle. Then using a static pH profile during this cycle is incorrect. Then you could also use a pH controller to do automatically what you do manually.

But to determine if you're regulator is rocksteady with BPM you can only determine with keep counting several times a day, every day in and out to get an average.

Or permanently log a digital pH profile to determine the natural rise and fall during the cycle. For that, you at least would need a Permanent pH probe and a Computer that logs it s you can review it.

If you don't do one or both it is and stays guesswork... Than no BBA means stable CO²?... And growing BBA a probability of unstable CO²?
 

Zeus.

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Such as CO² uptake by plants doesn't have an instant on and off switch. By references i read from very experienced (hobby) botanists it seems to work like an engine that needs to warm up and some time to reach the maximum uptake. Then we start an hour before lights on to get to a green DC and we administer a stable amount of BPM. Lights come on and we have X ppm CO². Plants slowly start to respirate need X time to come to a maximum uptake. But the BPM doesn't change, but more CO² is taken up. I never checked but is this is true then this can only result in an X amount of PPM CO² decrease in the water. It actually could be checked with permanent pH measurements. There should be a lower pH at lights on then you would measure at mid-light cycle.

And the logic in this says thus CO² can never be stable like this for the entire light cycle. Fixed CO² administering with a dynamic CO² uptake.

Great point Zozo :thumbup:, I had the same thought some time back and with the aid of my PLC and duel CO2 injection I do have a semi-dynamic CO2 injection rate to some degree, both on for pH drop till lights on, both off for few minutes then one on for 12.5 mins then off for 2.5mins whilst lights ramp up to about 75% then one on full time till CO2 off time. Does it help - dunno OFC but profile was more stable when I did it last.

Did use to use pH controller, but prefer the manually setting the on/off times esp with semi-dynamic settings I can use via my PLC.

Another thing to take into account in this story is Low Tech... :) I monitored the pH profile in my low tech for about a year with a permanent pH meter. And it was rock steady pH 6.8 at lights on and slowly rising to pH 8.5 at mid day. Till lights out then drop again.. This was averagely fairly static numbers every single day for the entire year.

Now if that aint unstable CO² i don't know what is.. Does this mean every low tech aquarium should be stacked to the top with BBA or an unsightly amount of algae in general?...

In my personal experience not always..

Another great point OFC, my take on this is the low tech tank handles it as the plants can manage the level of photo bombardment (aka -Light Intensity). If I turned down the lights on my tank to a similar level as yours I would need to decrease my CO2 injection rate to suit, but I would have sightly better growth as CO2 would be less limiting OFC. However if you turn your light up to my tanks levels then plant melt and the rest would follow OFC.

I think off it akin to 'suntan lotion' and the 'UV' level outside- when the 'UV' is low you dont need suntan lotion, when UV level is high you need it, there is an slight advantage to have it on all the time in the sun, however we do need out Vitamin D also.
 

Zeus.

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Yes indeed, looking at it from a natural point of view. There should be a pH rise and fall slowly over the entire cycle as it would do in nature.

But the plants have adapted to nature by natural selection, it doesn't mean whats natural is best for the plants, plants grow better with a less limited supply of nutrients esp CO2
 

dw1305

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Hi all,
6.8 at lights on and slowly rising to pH 8.5 at mid day.
That would be pretty standard for a low tech tank, even with reasonable flow. If you had a situation with lots of nutrients and lower flow, then you could end up <"with even greater variations">.

These occur in natural waters as well, where they are described as <"diel" pH variations>, the link has some values from a 12 month study of Esthwaite water
............Large changes in pH from 7.1 to nearly 10.3, and hence in concentrations of inorganic carbon species, were measured over a year. Carbon speciation and pH varied on a diel, episodic and seasonal basis. Diel variation of up to pH 1.8 was recorded........During autumn, winter and spring, the lake had concentrations of CO2* (free CO2) up to 0.12 mol m‐3 which is nearly seven times the calculated atmospheric equilibrium concentration so the lake will accordingly be losing carbon to the atmosphere. In contrast, during periods of elevated pH the concentration of CO2* was reduced close to zero and the lake will take up atmospheric CO2
cheers Darrel
 

zozo

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I'm having a small 50-litre outdoor aquarium in the garden for the last 4 years... It's bombarded with sunshine from 10 am till? well rather dynamic but up to 18 hours at the longest days.

As can be reviewed in my mission bathtub journals in the pond section.
https://www.ukaps.org/forum/threads/mission-bathtub-2019.56746/page-2#post-568163

And this little bugger baffles me each year again throwing tons of theories out of the window.

It gets next to no CO², 0 extra fertilizers and it grows plants like a champion never any algae not even that much on the glass. Maybe clean the glass panels once every summer.

It's a what you see is what you get.. My indoor tanks grow relatively speaking more algae than plants.
 

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