# Stable CO2



## Richard40 (31 Mar 2020)

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 (31 Mar 2020)

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. (31 Mar 2020)

Richard40 said:


> 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


----------



## Barbara Turner (31 Mar 2020)

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. 



Zeus. said:


> 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 (1 Apr 2020)

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 (1 Apr 2020)

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 (1 Apr 2020)

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.


----------



## Richard40 (1 Apr 2020)

My PSI is about 750 on the right dial and 30 on the left dial.


----------



## Zeus. (3 Apr 2020)

ceg4048 said:


> 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 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


----------



## zozo (3 Apr 2020)

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..


----------



## zozo (3 Apr 2020)

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 (3 Apr 2020)

zozo said:


> 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 (3 Apr 2020)

Witcher said:


> 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. (3 Apr 2020)

zozo said:


> 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 , 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.



zozo said:


> 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. (3 Apr 2020)

zozo said:


> 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 (3 Apr 2020)

Hi all, 





zozo said:


> 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 (3 Apr 2020)

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.


----------



## Witcher (3 Apr 2020)

zozo said:


> 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.



How it looks in the winter time? Because it sounds like great example of year cycle with no additional ferts - I assume plants feed themselves from winter/cold period leftovers after flowering and similar processes (rotten parts/leaves etc).


----------



## zozo (3 Apr 2020)

Witcher said:


> How it looks in the winter time? Because it sounds like great example of year cycle with no additional ferts - I assume plants feed themselves from winter/cold period leftovers after flowering and similar processes (rotten parts/leaves etc).



Last winter is actually the first winter ever it stayed outdoor. Last winter was extremely warm and it did rather well all plants in it did survive. But all previous years i took it indoors and under artificial light during the winter period to protect it against freezing solid and crack.

I can also assume a lot with this little aquarium, it started out as an experiment that surpiced me beyond expectation. I'm growing potamogeton gayi in it that i had as left over from my previous High tech aquarium. And i must say, it grows beter, larger, more colourful and faster in non co² under natural light than it did indoors with extra co².

This is how it looks today all winter outdoor. Never managed to develop this colour indoors under 8000 lumen and CO².


----------



## Tim Harrison (3 Apr 2020)

Richard40 said:


> 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.


A bubble counter is not a measure of CO2 conc., it's just a visual guide to help you dial your CO2 in accurately. George probably just mentioned it as a rough guide. Use a drop checker to gauge CO2 conc. It should be lime green at lights on and all the way till lights off.


----------



## zozo (3 Apr 2020)

Tim Harrison said:


> With regards the question of stable CO2. I think folk sometimes confuse unstable with unavailable. My understanding is that plants will adapt to their environment or ultimately die. For instance, plants used to a low-energy environment will adapt accordingly and compete to use up available CO2 at the beginning of the photoperiod. In this case the CO2 is not unstable it is just not available throughout the entire photoperiod.



I guess it's a good question to ask "What are the criteriums for unstable CO²?" I find the term unstable CO² rather confusing in it self. And in many threads at the end, it becomes even more confusing because there are so many individuals takes on it. 

But it must be possible to narrow it down in a simple summary everybody can understand.

To give a short summary my best guess. 

stable CO² =

1: A stable bubble count during the entire cycle.
2: A lime green drop checker at lights on.
3: Sufficient distribution/flow.
4: A good quality diffuser.
5: ? or more?

Then if one of these is not met, results in an unstable CO² distribution with all its consequences...


----------



## Zeus. (3 Apr 2020)

*Rubisco Wkii* , *Rubisco, Rubisco *- worth a read IMO

Quote
Rubisco is an enzyme involved in the first major step of carbon fixation, a process by which the atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose.

Some enzymes can carry out thousands of chemical reactions each second. However, RuBisCO is slow, fixing only 3-10 carbon dioxide molecules each second per molecule of enzyme. The reaction catalyzed by RuBisCO is, thus, the primary rate-limiting factor of the Calvin cycle during the day. Nevertheless, under most conditions, and when light is not otherwise limiting photosynthesis, the speed of RuBisCO responds positively to increasing carbon dioxide concentration.RuBisCO is usually only active during the day as ribulose 1,5-bisphosphate is not regenerated in the dark.

In spite of its central role, rubisco is remarkably inefficient. As enzymes go, it is painfully slow. Typical enzymes can process a thousand molecules per second, but rubisco fixes only about three carbon dioxide molecules per second. Plant cells compensate for this slow rate by building lots of the enzyme. Chloroplasts are filled with rubisco, which comprises half of the protein. This makes rubisco the most plentiful single enzyme on the Earth.

Unquote

So this fit the model of having a stable [CO2] during the main photoperiod, as rubisco is not generated in the dark - Which is what Clive tells us- So the pH spike at night is irrelevant


IMO appling Liebigs law enables us to have an unstable [CO2] and no issues ' in theroy'. As if the [CO2] is none limiting at any given time, then rubisco works faster (from above quote) , the 'expensive' production of Rubisco will not be needed 'as much' by the plant, and will not need to increase its Rubisco production therefore the [CO2] is irrelevant as long as CO2 is non Limiting.



zozo said:


> But it must be possible to narrow it down in a simple summary everybody can understand.



Sometimes it takes years of study to to understand some things as the complete pathway can/is quite complex and a simplification of it just doesn't do it justice


----------



## Tim Harrison (3 Apr 2020)

Zeus. said:


> IMO appling Liebigs law enables us to have an unstable [CO2] and no issues ' in theroy'. As if the [CO2] is none limiting at any given time, then rubisco works faster





Tim Harrison said:


> or at least maintain a conc. where limits to growth and competition between plants doesn't occur. Which is more to the point.






zozo said:


> I guess it's a good question to ask "What are the criteriums for unstable CO²?"





Tim Harrison said:


> If however the CO2 conc. is inconsistent or unstable, in that it varies, throughout the photoperiod and from one day to the next,


----------



## zozo (3 Apr 2020)

Zeus. said:


> Sometimes it takes years of study to to understand some things as the complete pathway can/is quite complex and a simplification of it just doesn't do it justice



Well, then it seems more complex than tools available to determine CO² stability. 

Makes it rather unexplainable, since you can't teach experience...


----------



## Tim Harrison (4 Apr 2020)

foxfish said:


> If you can offer alternatives I am sure many folk would be delighted find out how?


That is very well put foxfish. I'd certainly like to know more.


----------



## Andrew T (4 Apr 2020)

This is what “he” propagates on “other forums”:

“Low CO2 does no harm and is not critical in any way on its own. ADA tanks are evidence of this as well as my own experiments in my tanks. You can actually grow a nice tank in high light intensities without adding any CO2; it's a myth that high light requires high CO2. If the concentration of metals fall into the toxic range, that's when plants will have difficulty growing and maintaining good health. If the concentration is too far into the toxic range, no amount of CO2 coupled with high light intensities will alleviate it.“ - end quote

Now we know ADA tanks have very low light intensities (being tested in person with a par meter by Tom) and they also have the entire Japanese reserve army to keep the tanks clean of any algae at any given time of the day.

We also know by now high light and no co2 is a recipe for disaster, an algae soup very easily replicated over and over again.

I choose to go on with high co2 high flow and high fertilizers with lower light levels ....and get results.


----------



## zozo (4 Apr 2020)

Andrew T said:


> We also know by now high light and no co2 is a recipe for disaster



Could be, but not necessarily...

As stated before i experience the contrary each year again the last 3 summers and the 4th is coming and i don't expect it to be any different.

1th year, full blast sunshine all day long not 1 minute shade even on a rainy day it got more lumens than any lamp could provide, 0 algae, 0 fertilizer, natural CO² equilibrium. Super healthy plant growth.




2th year exact same setup, same substrate,  didn't change a thing, same regime, same story but some different plants. See the Lilaeopsis carpet.





3rd year.




Disaster? Yes it was a disaster to trim the plants... 

It seems there are no answers only statements and even more questions...

And not to make a statement but an assumption, a part believing without evidence. 

As said before it is what you see is what you get.. Proof in the pudding? I simply can not tell you why.

I must add, don't be fooled by its size, this little aquarium is hooked to a 350 litre planted sump.


----------



## Tim Harrison (4 Apr 2020)

zozo said:


> 1th year, full blast sunshine all day long not 1 minute shade, 0 algae, 0 fertilizer, natural CO² equilibrium. Super healthy plant growth.


I think 0 fertz is probably key. I'm guessing the substrate had enough nutrients to feed the plants. And we also know that high density plant biomass infers a great deal of biological stability. And the floating plants would quickly soak up any excess, starving algae. I know Darrel @dw1305 has high light low-energy tanks using a similar principle, with lots of floating plants.

I experimented with this a few years back now. 2xT5 HO lights over a densely planted low-energy with minimal fertz input, most of the nutrients in the soil. And it remained remarkably algae free for several months. I think the ADA system isn't that far removed from this also. Very nutrient rich soil and lean dosing. Filipe Olivera also uses a very similar technique.

It doesn't really contradict what we already know, and like I mentioned before the CO2 conc. isn't unstable just unavailable for part of the photoperiod. Some plants will adapt very well to this environment since they use other pathways to synthesise carbon, e.g. vallis is very good as using bicarbonates.

High light, low-energy, soil substrate tank


----------



## zozo (4 Apr 2020)

The substrate used was 4 litres Velda Lelite Blue clay, the rest river sand and gravel. And it kept up for 3 years now...

This year i'm planning to strip it and do something different.. Not yet decided what..

Any suggestions? I'm in for a new experiment.


----------



## Tim Harrison (4 Apr 2020)

How about planting a few swords? It'd be nice to see some slightly more exotic looking emergent growth and maybe flower spikes 
Is a new mission imminent?


----------



## zozo (4 Apr 2020)

Tim Harrison said:


> How about planting a few swords? It'd be nice to see some slightly more exotic looking emergent growth and maybe flower spikes
> Is a new mission imminent?



Absolutely imminent. 

That is a nice idea. Thanks Tim... I can imagine it looking great, planting a variety of swords in it..

Tho i have a few Swords (Kleiner Bär) in the tub from the start and experience them problematic surviving the winter indoors. Planted them on an inert substrate (frit glass), they grow well in the summer but wither away again in the winter indoors and then i have to start over from scratch again. Due to light deficiency i guess. Or a combination of light and fertilization. Till now they came back each year again, but never really very strong.

I could give it a go, to plant them in this tank on a heavy clay substrate and see if it makes a stronger plant with more mass at the summer's end. An experiment well worth a try...

Have to do some reading about the best varieties i can choose from... Flowgrow has a complete thread on growing them emerged "<The Year Of Echinodorus>". It's loaded with pictures about growing them in the garden. There i'll find my answers.. 

Bellow an old picture from a few years back, all other years it got completely overgrown with other plants.


----------



## Tim Harrison (4 Apr 2020)

zozo said:


> Absolutely imminent.


Awesome, summer wouldn't be the same without it


----------



## Andrew T (4 Apr 2020)

zozo said:


> Could be, but not necessarily...


Zozo not to be contradictory I’m just raising some questions. I see some piping next to the tank feeding water to it. Is that some sort of continuous fresh water supply?
Have you ever tested your tap? What’s it like? We see high PO4 and NO3 straight out of the tap in some areas of the world while other areas are completely depleted of them.
The statement that no other lamp could provide what the sun provides in terms of light intensity is I’m afraid not in line with reality. 
I burned many SPS corals in my system over the years and others have done the same because of too much light (350-500 PAR at the upper 1/3rd of the tank) yet they remain in great shape in the Great Barrier Reef unless very high ocean temperatures trigger a mass bleaching.
What I’m trying to say is yes artificial light can be more intense than natural light .
Your outdoor tank doesn’t tell us the whole story with statements like “no nutrients and more light than any indoor lamp”.
Then we have the natural path the sun follows with the most intense output just for a few short hours, the rest is less so. Most of indoor tanks (more so the ones having issues) just blast the plants for 7-9 hours with high light continuously ; there’s rarely any ramp up and down of the light to mimic natural setting.
Clive implements it in his tank and his statement made a lot of sense; plants need a little time to get up and go just like we need time when we wake up to get dressed eat breakfast then go to work.

Again, it would be nice to know the source of your water and parameters and if you could have access to a PAR meter to put some numbers on those claims.
Not disapproving of your method, just that we need factual statements before drawing any real conclusions.


----------



## doylecolmdoyle (5 Apr 2020)

Personally I just run my co2 24/7 at a slow steady rate, I only grow slow growing easy plants, that probably dont need co2 but I find it just helps keep everything stable, I also dont use any nutrients these days and the tank is fairly algae free



untitled-2366.jpg by Colm Doyle, on Flickr


----------



## zozo (5 Apr 2020)

Andrew T said:


> Your outdoor tank doesn’t tell us the whole story with statements like “no nutrients and more light than any indoor lamp”.



I didn't state "No Nutrients"  I said "No Fertilizer" and that is something completely different... Obviously the plant needs nutrients to live and likely got some nutrients from something, from the clay substrate, fish poop, any other natural means the water column brings them. I do not add anything extra on top.

And for so far, i should have said any indoor lamp available to my budget yet can't compete with what the sun provides.
I'm not aware of any product that claims to be equal or stronger than the Sun...  Indeed that and my doubts don't say it isn't out there. You got me on that one...  But i guess if it exists you have to reach very very deep into your pocket to obtain it as a hobbyist. And need some darn good sunglasses while watching your tank.



Andrew T said:


> I see some piping next to the tank feeding water to it. Is that some sort of continuous freshwater supply?



Nope, It's an old Zinc bathtub and a sort of aquaponic filter and a little aquarium hooked together. Approximately 350 litres, it's a closed system that needs an occasional water change if i like to add fresh water. And if then this is Tapwater which is pretty soft gH4 / kH10.
>20 mg/l NO³ and 0 PO4.

I have no access to PAR meters i probably never will have, it's out of my budget and comfort zone of interest. And from what i understand even if i would have, it still wouldn't be a conclusive number. Because from what i understand from very knowledgeable botanists working in this field. We actually need to know the PPFD before PAR says something.

I'm trying not to make statements and even fewer claims. For the biggest part the conclusion i draw to myself is, i don't really know. That's why i simply share an experience and say "It's what you see is what you get." and i can't tell you why. It is what it is...


----------



## Zeus. (5 Apr 2020)

Andrew T said:


> Zozo not to be contradictory I’m just raising some questions.



I think we are all on the same page i.e.we are having a discussion aka peer review, no body is saying these are the facts and we are all open minded on the subject 



Andrew T said:


> The statement that no other lamp could provide what the sun provides in terms of light intensity is I’m afraid not in line with reality.



Think @Andrew T has made a very valid point here esp we consider Reflection and Refraction with our tanks with fixed lights the incident angle is constant so the light intensity will be constant if the lights output remains constant. However with natural light the incident angle of the light will be constantly changing as well as the light intensity, also the incident angle will change on a daily basis as the sun climbs/falls in the sky. So maybe our fixed lights above our tanks do bombard our plants with more photons than a tank receiving natural daylight light in a single photoperiod, not says always do, but maybe more than with think


----------



## zozo (5 Apr 2020)

I found a report from a meteorology institute with sunlight Lux measurements somewhere in the average middle of my country, which is approximately for the biggest part situated 5 metres below sea level. This would mean the same measurement done at places above sea level would give higher numbers. Since at the top of one of world's highest accessible mountains it's measured 5 x higher.

The report doesn't say day time and date but we can assume it's an average throughout clear sky days.

Results are:
Direct sunlight: 130 000 lux
Indirect - Daylight: 20 000 lux

Compared to a Phillips HPI-T Grow light 1000 watts Metal Halide = 85000 lumen

Lux = Lumen/m², Correct? Meaning in case of artificial light according to the height of the lamp placed above the surface it should illuminate means less lumen/m².

Actually no idea how it relates exactly and how Phillips measured it, i guess to put it in a reflector and make it illuminate 1m² exact and take some Lux measurements. At whatever. a height that maybe. Anyway a pretty darn beast of a lamp not yet coming close.

Another experience i did that made me wonder. I once had a lily flowering in of my at the time High Tech aquarium in the month November. It was illuminated with about  10.000 lumens LED fixture x 50cm above the tank. And daylight flowering lilies, close their flowers when its getting dark.



The fun part that baffled me was... The tank stood 1 metre next to a North-East facing window receiving a tad indirect daylight. The lights were on till 9 pm, but the sunset was at around 6pm. And despite the LED lights still operating at 100% at 6pm the Lily flower closed 3 hours to early. It didn't react to the artificial light but rather to the indirect daylight from outside.

Made me scratch behind me ears and wonder what is in the light? Why does my Lily flower prefer the low natural daylight during wintertime above my 10.000 lumen LED fixture?

I don't know, it just did.

Was it the intensity or is artificial light missing some parts of the spectrum the plant reacts to? It beats me and knocks me off my shoes..
Another what you see is what you get mystery.


----------



## Zeus. (5 Apr 2020)

[QUOTE="zozo, post: 592866, member: 13448"
]Direct sunlight: 130 000 lux
Compared to a Phillips HPI-T Grow light 1000 watts Metal Halide = 85000 lumen[/QUOTE]

So sunlight is double the Metal Halide but relatively the same order of magnitude

Light penetration into fresh water





So therefore the light absorption coefficients will be higher in our tanks with artificial light compare to natural sunlight due to the incident angle of the light source.

So I would wouldn't be surprised if the Grow light 1000 watts Metal Halide yield more lux/PAR then natural sunlight at any given depth in our tanks and the incident angle of the metal halide is constant, but the sunlight is variable though out the day so the net light will also be greater with the metal halide also.


----------



## dw1305 (5 Apr 2020)

Hi all, 
I'm pretty sure that light intensity at midday in the tropics is going to be an order of magnitude larger than anything that we can produce with a lamp. I'll try and find a reference that quotes the different measures of light intensity. For sunlight you should be able to equate light intensity with PAR.  

cheers Darrel


----------



## jaypeecee (5 Apr 2020)

zozo said:


> I guess it's a good question to ask "What are the criteriums for unstable CO²?" I find the term unstable CO² rather confusing in it self. And in many threads at the end, it becomes even more confusing because there are so many individuals takes on it.



Hi @zozo 

You may want to cast your eye over this thread that I started in October last year:

https://www.ukaps.org/forum/threads/fluctuating-co2-levels.58757/

JPC


----------



## zozo (5 Apr 2020)

Zeus. said:


> So I would wouldn't be surprised if the Grow light 1000 watts Metal Halide yield more lux/PAR then natural sunlight at any given depth in our tanks and the incident angle of the metal halide is constant, but the sunlight is variable though out the day so the net light will also be greater with the metal halide also.



I envy you that you understand all this matter... But who in their right mind (No pun intended) illuminates an average indoor aquarium with an 85.000 lumen 1000 watt Metal Halide? Would be quite a task to daily top off evaporation.


----------



## Tim Harrison (5 Apr 2020)

Regarding incident angle of the sun, remember it's also an aquarium with glass sides so that doesn't necessarily apply in exactly the same way as it would to a lake or pond etc; it could potentially get a lot more sun.



zozo said:


> It's an old Zinc bathtub and a sort of aquaponic filter and a little aquarium hooked together. Approximately 350 litres, it's a closed system that needs an occasional water change if i like to add fresh water


That constant flow of water filtered through high plant biomass could also be an additional reason the aquarium is algae free, especially when you consider the aquarium is only a relatively small window on what must be an incredibly stable system


----------



## zozo (5 Apr 2020)

Tim Harrison said:


> Regarding incident angle of the sun, remember it's also an aquarium with glass sides so that doesn't necessarily apply in exactly the same way as it would to a lake or pond etc; it could potentially get a lot more sun.
> 
> 
> That constant flow of water filtered through high plant biomass could also be an additional reason the aquarium is algae free, especially when you consider the aquarium is only a relatively small window on what must be an incredibly stable system



That's also my best guess..  Plant mass is king! And before it has this i always see algae growth, but it vanishes as soon as the plants kick in as soon as sun intensity goes bonkers.


----------



## jaypeecee (5 Apr 2020)

Hi @zozo 

I'm trying to fathom out the link between CO2 and Mungo Jerry! Great to see the video though. Brought back memories of my youth.

JPC


----------



## dw1305 (5 Apr 2020)

Hi all, 





jaypeecee said:


> I'm trying to fathom out the link between CO2 and Mungo Jerry!





zozo said:


> And before it has this i always see algae growth, but it vanishes as soon as the plants kick in as soon as sun intensity goes bonkers.


In the summertime.......

cheers Darrel


----------



## jaypeecee (5 Apr 2020)

dw1305 said:


> In the summertime.......



I also wondered if that may be the link.

JPC


----------



## Zeus. (5 Apr 2020)

zozo said:


> illuminates an average indoor aquarium with an 85.000 lumen 1000 watt Metal Halide?



well the running cost would be quite a bit alone. But yes I must confesses I had overlooked the amount of light the Hetal halide was outputting 

Checked out the ADA RGB solar for comparison





which has an output of 3000-3500lm  which converts to 21,000 Lux output at 30cm above the water (Lux (*lx*) measures illuminance, which is the amount of light on a surface per unit area.) at 30cm above the water

So for the Phillips HPI-T Grow light 1000 watts Metal Halide the output in lux would be height and reflexor dependant as well, with the right reflector and 30cm from water it would make the direct sunlight seem dim.

But yes direct Sunlight has x5+ the output in Lux than an ADA RGB Solar, but ADA solar directly above tank so incidence angle better so more light will penetrate, we would need to calculate the Solar Zenith Angle. At the equator its 90 degrees and for Me and Zozo its about the same all year round maxing at about 60 62  degrees* Here*

So without doing the maths OFC with an incidence angle of 60 degrees for the Sun and 90 degrees for the ADA RGB solar it would be a close race on a mid summers day, but for a six hour period think the ADA light would yield a higher net value


----------



## zozo (5 Apr 2020)

dw1305 said:


> In the summertime.......



We are Happapy!.. ......


----------



## Tim Harrison (5 Apr 2020)

zozo said:


> That's also my best guess..  Plant mass is king! And before it has this i always see algae growth, but it vanishes as soon as the plants kick in as soon as sun intensity goes bonkers.



Those mutton chops can't be real, they must be self-adhesive or attached using Velcro on or something


----------



## jaypeecee (5 Apr 2020)

Hi Folks,

I see no mention of PAR in the _ADA Solar RGB_ spec. Par for the course (pun intended). No spectrum either - therefore difficult to compare with sunlight.

JPC


----------



## Zeus. (5 Apr 2020)

jaypeecee said:


> Hi Folks,
> 
> I see no mention of PAR in the _ADA Solar RGB_ spec. Par for the course (pun intended). No spectrum either - so difficult to compare with sunlight.
> 
> JPC



IDD  Typical manufacturers using units of measurement that we are not really interested in Lux and lumen when all we are interested in is PAR, but you have to use what you can to compare.


----------



## Bryce (5 Apr 2020)

Well this subject has been a good one . The OP original question sort of got lost . [Hi what’s the best way to know you have stable CO2? ] The answer is do you have good plant growth? You can measure, test etc.. but it’s simpler than that.. do you have minimal algea? Are your plants growing?  I’m not a scientist ,biologist  or plant expert by any means. I’m just a guy who enjoys growing plants in a tank full of water no more no less. I can’t answer all the science questions but, a little common sense will go a long way.


----------



## dw1305 (6 Apr 2020)

Hi all, 





Bryce said:


> Well this subject has been a good one . The OP original question sort of got lost . [Hi what’s the best way to know you have stable CO2? ] The answer is do you have good plant growth? You can measure, test etc.. but it’s simpler than that.. do you have minimal algea? Are your plants growing?  I’m not a scientist ,biologist  or plant expert by any means. I’m just a guy who enjoys growing plants in a tank full of water no more no less. I can’t answer all the science questions but, a little common sense will go a long way.


I think you have to differentiate between low tech and hi tech.

In a low tech, the plant mass is going to effectively deplete the CO2 during the photoperiod, you can get a measure of this by the variation in pH (as the CO2:O2 ratio changes). A larger plant mass will deplete that CO2 more effectively, it's back to <"Canford Park again">. During photosynthesis one molecule of O2 is produced for every molecule of CO2 incorporated. Because plants are carbon based, and they grow, we can see that they are net CO2 consumers and net oxygen producers.

There are ways of "flattening the curve" of CO2 depletion, the one I would recommend would be increasing <"the gas exchange surface area">. There is a much fuller discussion of this in <"maxing CO2 in Low Techs">, where this graph comes from.




Partially why I like a floating plant in the tanks is that they aren't ever CO2 limited, they have <"Diana Walstad's "aerial advantage">. This is also why I think that the <"no water changes, low tech because they cause CO2 fluctuation"> isn't an argument that holds any water.

*High Tech.*
I'm not a CO2 user, but I think the idea behind the "stable 30ppm of CO2" during the photoperiod was so that plants aren't carbon limited, and can effectively make use of the PAR and nutrients available to them. You can still end up in a situation where CO2 is depleted (because PAR drives photosynthesis), but you can't safely go much beyond 30 ppm CO2 without asphyxiating your fish. If you don't have any livestock you could definitely add more CO2 and the plants could then utilise more PAR and nutrients.

cheers Darrel


----------

