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Not sure if there is an issue or if patience is the virtue

I cannot say that pogo is growing because it is just slowly dying off; the little sprout there may have been from when I bought them (I am not sure - I will pay more attention). I suspect highest compensation point than any other plant in my tank. The S. Repens has not grown or died --> likely root growth then? Again, lower compensation point.

Dont forget some plants will just fail in your setup no matter what you do, Darrel uses the three strikes and your out, I tend to give them less chances unless I really like the plant

Have you seen a situation where CO2 is non-limiting, but light does not meet the compensation point?

Every time the light goes off ;) or when a plant gets shaded by other growing plants so all the time esp after a big trim.

<-- only if it is not outcompeted/chemically warfared by surrounding plants; if my nutrients (co2 and ferts) have enough balance to handle higher PAR levels, then I should not see an algae bloom when increasing light. Yes/no?

Plants can only handle so much light IMO even when there unlimited nutrients ( CO2 is a nutrient OFC)

1 unit of CO2 is used for every unit of light. I.e. 30PAR should use 30 ppm of CO2 at the substrate -

dont think there is a formula 'yet' - trail and error

I 'try' to focus on growing the plants and then the plants out compete the algae, which is what must scapers advise. If you get a bloom there is usually a good reason


Not sure on the cool white bit: His ratio of red:coolwhite (625nm: 5000k) is the same -- and so I think I should increase my cool white as well to this. I am not sure how to obtain those 6500 and for all I know, my cool white may be 6500 -- will do research.

Go for the colour you like and the plants will use what they can. The most efficient use of watts input to what the plants can use will probably not be the most aesthetic.

if there is no algae bloom after increasing the light

Some algae blooms are inevitable with a new tank and part of the cycling process, but the higher the plant biomass the less likely the algae bloom.

then would you say that there is enough CO2/flow in the tank for that PAR output?

When healthy plants are growing faster than the algae, there will always be some aglae in your tank, mine is full of algae all types BBA, GDA, BGA ....... but is all under control and the plants out compete the algae as a general rule and the 'cleanup crew' me, WC, shrimps and snails keep the algae in check.

Or is there another indicator that I can and should use.

Only one worth using IMO The plants - just watch them.

Dont make too frequent/many adjustments other wise you will lose track of what you have done and it takes 4-5 weeks to see if it has worked, unless there is a sudden downturn, plus if you change too much which one did the trick and one may counter the other eg better flow may resolve the present issue and increasing the light may return the issue at the same time !!!!
 
I am going to make a few posts to address things 1 at a time:
1) this one for the McCree curve -- really neat findings.
2) Comment on progress on tank
3) Respond to posts

First, I have attempted to cite everything - I didn't go formal (APA,IEEE, etc) but I do want to give credit where credit is due, so if you see any error with my citing, let me know.

It starts here:

Well, after some coffee.


Quoted here: http://econoluxindustries.com/McCree-curve.html


Paper: [1] "The action spectrum, absorptance and quantum yield of photosynthesis in crop plants" - McCree, Keith J. Agricultural and Forest Meteorology 9: 191-216. doi:10.1016/0002-1571(71)90022-7


"The action spectrum, absorptance and spectral quantum yield of CO2 uptake were measured, for leaves of 22 species of crop plant, over the wavelength range 350 to 750 nm. The following factors were varied: species, variety, age of leaf, growth conditions (field or growth chamber), test conditions such as temperature, CO2 concentration, flux of monochromatic radiation, flux of supplementary white radiation, orientation of leaf (adaxial or abaxial surface exposed). For all species and conditions the quantum yield curve had 2 broad maxima, centered at 620 and 440 nm, with a shoulder at 670 nm. The average height of the blue peak was 70% of that of the red peak." [1]



n4_yvDLIa9NB-E2AQPEmrKK2oWNhL0DJJJXMaTgZox6YCD0OFj.png




"The Quantum yield Φ of a radiation-induced process is the number of times a specific event occurs per photon absorbed by the system." (https://en.wikipedia.org/wiki/Quantum_yield)


I.e. McCree found that given 1 photo of light with a specific nanometer, the number of times that the event of uptaking CO2 happened a specific percent of time --- in other words, given 1 photon of 600nm red light, the event of CO2 assimilation occurred 100% of the time.


But the event still occurs for every wavelength of light - hence the often quoted, “any light will grow plants”. Some people don’t care about spectrum - But the plants respond BEST to red … what happens to the rest - it tans my skin - OR perhaps algae will utilize other colors better? Maybe not - it is a plant after all. I am not sure.


This is was cool, but it left me with the question -- well how MUCH CO2 is that actually?

To answer this question, we need to know how many photons of light are passing through our system and how much each photon actually uses.

From here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3442562/

Hogewoning S.W., Wientjes E., Douwstra P., Trouwborst G., van Ieperen W., Croce R., Harbinson J. (2012). … did some research:

Underlying causes of the wavelength dependence of quantum yield. Quantum yield for CO2 fixation for 18 different wavelengths calculated from gas-exchange measurements (black solid lines) and from the in vivo efficiency balance between the two photosystems (red dotted lines). The difference between the values obtained by the two different methods at wavelengths <580 nm represents quantum yield losses attributable to light absorption by photosynthetic carotenoids and nonphotosynthetic pigments. (A), (B), and (C) correspond to leaves grown under the sunlight spectrum, the shade light spectrum, and blue irradiance, respectively. (Reprinted from Hogewoning et al. [2012], Figure 8.)

pL3ZFn_zBH0QORqc1_LrvQwgFd1hrKa7xyb5dwxbpWFqUIFMln.png



What this means is that at each of these specific wavelengths (just as McCree did), a certain amount of MOLS of CO2 is absorbed under these circumstances.

“In contrast with previous studies, the authors assessed the wavelength dependence of quantum yield on an absorbed light basis (termed α)”

Now, “They show in particular that photosystem efficiency balance, reflecting the ratio of photosystem I:photosystem II reaction centers, has a strong impact on α (see figure above).”


So this means that the balance of our light output matters -- we can’t just willy nilly assign %’s to spectrum and think we have efficiency -- but clearly the lines look similar … plants will grow with the light.


In: https://books.google.ca/books?id=cnXBnaEFhPwC&pg=PA11&lpg=PA11&dq=0.093+CO2+fixed+per+absorbed+photon&source=bl&ots=M7OwDsjwJn&sig=ACfU3U2fjbhCjlaDTQm9OxrpxdwUQh0KEA&hl=en&sa=X&ved=2ahUKEwjM55nc_-LoAhXETd8KHcM-AoYQ6AEwAnoECAwQJw#v=onepage&q=0.093 CO2 fixed per absorbed photon&f=false


We have,


hQje7qlVnB_1NsoQSQHCcg_gq5GSpwcIn7zf5BB3fLql0pG57J.png



I think what is more interesting, rather than trying to dig for all of these papers and confirm everything, is that this number of .093 mol per mol absorbed photons is similar to the above paper.


Let’s go with it.


A key is ABSORBED photons -- this is where all of the calculations below will become skewed -- the photon needs to hit the plant -- hence why plant density is actually important (we increase the probability that a plant will be hit by a photon of light and increase the probability that there is CO2 by that plant with good distributed flow and high concentrations of CO2 and increase the number of photons by HIGH PAR).


So, let me assume that my PAR is
sGYkyXjAEtek4SracmeUm5TLL8zCLVmD0MIewrst_ZlJ9ngI1J.png
(you need light to get there) at a 2D cross-section of my aquarium. This means, that in a 2D slice 1m x 1m, I have
1A_prOn_4_JiLgLZcOIjf2pr_LGTEihcariWK1GtNVAg7CgBXO.png
of photons of light passing by per second. In other words, I have
ISt2MNN0KzAe4YRV8OmqDMw_vZhRUGP9d0OTaQMWLiEg4w8flA.png
of photons of light passing by per second. But recall, that each of these photons from our lights could be a different wavelength and has a different relative quantum yield …. So let’s just say that:

For each mol of photons, we absorb .093 mol of CO2. -- we can go ahead and look at percent distributions based on settings etc -- but if just assume everything absorbs like red, then we overestimate the amount of CO2 ... and that uses ideologies of EI ... so......

The natural question is how much CO2 is in my 2D 1M slice … but my tests (pH probe, drop checker) correspond to 3D … so what do we do.

Ideally, if I jam pack that 1M square slice with the appropriate amount of CO2, ferts, and plants to absorb this light and use the nutrients, then I will have great plant growth and release allelochemicals to inhibit algae! Once the plants use it, I just need to make sure I have enough flow so that I replenish them before they are depleted (in the appropriate ratio)? Ensure all is non-limiting
.
This is what these beautiful tanks are doing.


Let us assume we have 30ppm CO2 in my 65 gallon tank (I just made it 60 to accomodate for hardscape) (I cannot speak to the distribution in solution here). This means that we have .68 mol/L of CO2 via.


QsVbqJ2Nz6qd6FANt5FdjVb22-JpATpPBMpM0YmivSjMNNubti.png




We need mols, so that we can compare it with uptake of photons.


How many photons do we have in at the 2D cross section of my tank each second? My tank actually only constitutes
CodY_mZG0V3hzWyD4NTxTuSDouxlIp9lEla4UYI4gJ6R2HKAME.png
of the 1M square cross section. So, I have
azxp0XZlvG2CgUq1FMCKVUC8bNQpO4paBIs2UVXG0Vtd1FFhPm.png
of photons passing through my tank at every given second.



For each mol of photons THAT HIT A PLANT, we absorb .093 mol of CO2 from the water column.


Sooo… I need .000001225 mol CO2 present everywhere in my tank at every second.


XizM9jl4p9Y8HzjxxG2yzH_smLLGNu5hnJhTYYcrSbgkvcg2eu.png




How much do I actually have?


I have no way of knowing what percent of my tank is actually covered in foliage (this would tell me how much of my CO2 in the water column is wasted) -- so let’s say that I have 1% of it that is actually effective. Even if we drop it lower, you will see soon that it doesn't make a huge difference.


This means that of my .68 mol of CO2, I actually have .068 mol of CO2 that my plants can use. At 30 PAR, this will last me 5440 seconds at 30 PAR or 90 minutes (don't forget my PAR also changes as we go deeper sooo.... more variables). That’s why we can turn the CO2 off early -- if we account for loss from everything else that is going :).


xiA01EWvTBTUtMWjI06wPG4JD_fCpjWvj03ciLa_6FlXWqk3A0.png



Now, my filter is 300GPH, so I am replenishing this (if good flow distribution) at .315 litres/second. So, my CO2 will be depleted faster than I can replenish it - but fast enough. Not everyone advocates for exhorbitant amounts of flow and I think this is why.

We could develop functions to graph the relations between depletion and replenishment but I think that is where the next part comes into play --- and our plants tell us @Zeus. ... well they tell me LOL.

IMPORTANT

The Quantum Yield refers to the initial rate that the different chlorophyll excitations occur. And as @dw1305 said, these excitations do even out at a “maximum” -- so there will be an equilibrium somewhere and that is what we are trying to find with a stable pH during the photoperiod -- and as we know it takes time for the plant to reach that equilibria this is why we need a ramp time!

I think I can safely say that in my plants, cellular respiration was occurring at a rate faster than my photosynthetic rate, and I was not reaching the compensation point -- the picture below from https://www.encyclopedia.com/earth-...lism/environmental-studies/compensation-point demonstrates what I think happened. I had enough CO2 but there were not enough photons to assimilate them. @alto

6049637.gif


-- In my next post I am even more certain about this.

If anyone sees any errors let me know.


With regards,

Josh
 
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Hi again,

Here is a link to a video of the tank after the 1 hour peak in the photoperiod. NOTE: When the video zooms in what you are supposed to see is an intense stream of bubbles leaving the plant -
1) the s.repens from underground, must be the roots
2) the java fern from its rhizome,
3) and the ludwigia from its stem.



The quality sucks, but it gives an idea to anyone watching this thread of what happened.

I increased my lights:
B 10%
G 50%
R 100%
WW 100%
CW 100%

Photoperiod has a 2.5 hour ramp up to max for 1 hour, then a 4.5 hour ramp down.

First note: no algae.

Second: Those streams of bubbles are evidence of photosynthesis and based on some reading it is based on damage in the plant ... all of my plants are damaged? ** see 1) 2) 3) ** from above.

In the video, if you squint hard enough, you can see what I suspect is pearling. The Pogo pearled on 1 of the leaves as well, just 1, the rotala none, the s-repens yes, the epiphytes yes, the crypts yes.


My hypothesis is that I was indeed below compensation and my plants were respirating to death.

I noticed this:
1


The lower part of that rotala is dieing but the top is nice -- I have no clue why but maybe it was trying to grow in the light it had, expedite it's resources so that when it eventually pops off, it could replant itself somewhere via the current?

I want to note that I have not adjusted my flow at all since this.

THE IMPORTANT QUESTION: What do I do now? Is that enough light? Does pearling like that mean that it will eventually heal itself?

Some next steps that I will do for sure:
1)
better my flow distribution with a spray bar.
2) daily water changes to remove excess organics from all my die off.
3) Continue my dosing regime

Is it time for patience?

Josh
 
Dont forget some plants will just fail in your setup no matter what you do, Darrel uses the three strikes and your out, I tend to give them less chances unless I really like the plant

I had not even considered that a plant would fail in a setup -- interesting.



Every time the light goes off ;) or when a plant gets shaded by other growing plants so all the time esp after a big trim.

But those plants that get shaded, do they continue to grow properly or do they eventually not make the compensation point and end up dying? I have no experience on shading plants because my other plants grow so well and bushy LOL.

Plants can only handle so much light IMO even when there unlimited nutrients ( CO2 is a nutrient OFC)

Is that not what makes them turn red etc? When they have too much light, they adapt to reflect the red light to minimize the amount of light they actually absorb? I think you are right though, when measured with growth - that is what EI did ... push those plants with as much light until they just don't take up any more nutrients -- but if people dose 3,4,5x EI, then does that mean that the ceiling is pretty high?


I 'try' to focus on growing the plants and then the plants out compete the algae, which is what must scapers advise. If you get a bloom there is usually a good reason

Got it - thanks.


Go for the colour you like and the plants will use what they can. The most efficient use of watts input to what the plants can use will probably not be the most aesthetic.

Some algae blooms are inevitable with a new tank and part of the cycling process, but the higher the plant biomass the less likely the algae bloom.
I see that now :) - thank you.


Some algae blooms are inevitable with a new tank and part of the cycling process, but the higher the plant biomass the less likely the algae bloom.

Only one worth using IMO The plants - just watch them.

I also mention this in the post on the McCree curve -- I will go tag your thought in there now!




Dont make too frequent/many adjustments other wise you will lose track of what you have done and it takes 4-5 weeks to see if it has worked, unless there is a sudden downturn, plus if you change too much which one did the trick and one may counter the other eg better flow may resolve the present issue and increasing the light may return the issue at the same time !!!!

Luckily, I am forced to since I do not have any other equipment right now :p. If things start looking up, then leave it?

Thanks for all the support on this @Zeus.

Cheers,
Josh
 
I feel that I should update this thread and potentially bring it to a close for anyone watching.

My issue was light. I was not reaching the compensation of my plants due to the low intensity and the depth of my tank. I can update over the next few weeks, but as of tomorrow, I may be tweaking the flow to optimize it so I cannot say that it was one or the other.

My plants are growing, and there are no algae blooms. Pictures below
0

0

0


Since I am EI dosing, I hope not to run into any deficiency OTHER than CO2 --- I am hoping that I will have an increased growth response and delivery of nutrients when I add the spray bar and better distribute my flow. The fear -- to not break a good thing.

Note that I cannot say that fixing my flow distribution would NOT have fixed my problem, but I can say that it looks like light did.

Thanks UKAPS.

Josh
 
1 unit of CO2 is used for every unit of light. I.e. 30PAR should use 30 ppm of CO2 at the substrate...Definitely need some confirmation/explanation here.

Hi Josh (@Plants234)

What did you mean by '1 unit of CO2'? Unfortunately, there is no simple relationship between PAR/PPF* (micromoles/sec) and CO2 consumption. Not that I'm aware of. If only it was that easy!

JPC

* PPF = photosynthetic photon flux
 
Hi again, Josh (@Plants234)

I don't know how I had managed to overlook this thread. Some interesting stuff here. I am very interested in the topic of aquarium lighting. Indeed, I designed my current aquarium lighting and got it built by the very same company as that used by Dennis Wong. The company's name was BuildMyLED (BML) and who are now Fluence (Osram). Will read through all the posts here with much interest and, hopefully, reply again tomorrow. There just aren't enough hours in the day. And I say that as someone who is now retired!

JPC
 
Hi @jaypeecee!

Good to hear from you again!

What did you mean by '1 unit of CO2'?
Later in the thread, I went and learned about the McCree Curve; I hope that my post there helps.

Unfortunately, there is no simple relationship between PAR/PPF* (micromoles/sec) and CO2 consumption

The finding that I posted after the McCree gave some insight into this - but only for C3 plants; I am not going to pretend to know anything about this. But I can say that a quick google gave me, "C3, C4, and CAM photosynthetic pathways are present in aquatic plants." (https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3040.1992.tb01653.x).

It said 1 "unit" (in these cases it is mols) of photons basically consumed 1 unit of CO2 (is good enough for me). -- We need to figure out what is the likelihood that that photon that hits our plant that forces photosynthesis to happen, actually has all of the nutrients readily available UNTIL the next photon hits. I think each part of the photosynthetic chain actually needs a photon of light, but I am not going to pretend here.

That is where I said 1% of my CO2 is accessible where I continued my pseudo-approximation.

I think the moral is that explains why good flow (provided you have enough light) solves problems. It increases the probability that CO2 will be there at this point in time when the photon actually makes contact - not to mention the other nutrient delivery.

It also explains (to me at least) why the sweet spot for light for co2 for your tank exists!

When the rate of co2 is not turned over quick enough to keep up with the photon of light that requires a co2 molecule, we have an imbalance and the opportunistic algae takes over.

PS . I just installed the spray bar and can say that this flow distribution is like nothing I have seen before.
upload_2020-4-15_21-37-44.png


It is this excellent churn. Anyways, let's see what practice brings us.

Cheers,
Josh
 
Hi all,
The finding that I posted after the McCree gave some insight into this - but only for C3 plants; I am not going to pretend to know anything about this. But I can say that a quick google gave me, "C3, C4, and CAM photosynthetic pathways are present in aquatic plants."
Aquatic plants are nearly all C3 plants, a few Isoetids are CAM plants.

cheers Darrel
 
Ok bringing this thread back to life!

First, I found this thread: https://www.ukaps.org/forum/threads/effects-of-too-little-light.34259/page-2 It addresses the same issues I was having ... except my most recent issue which address the topic of the thread.


Below you can see some photos of the new growth in the tank.
1

1

1


The rotala is freaking me out a bit -- in the middle of the photoperiod, it looks strong and then the morning after it wilts (more information to share about why I think this might be below). See the photo below.
1


Notice the rotala new sprout is becoming thinner (only after the morning).

Here is the information we need. Since extending my photoperiod and increasing my intensity, I had great plant growth, but I think my plants still suffered the effects of no growth for so long. Shortly thereafter, I noticed some algae on my S. repens (photo below) - not sure what kind it is - and I immediately reduced my light intensity in response (was this the right idea or was this merely expected because of the circumstance, and I should have left it running?).

1


Notice that the algae is only on the old leaves. Will the new growth overshadow the algae and eventually outcompete it? Do I trim it? Do I just be patient at the current and wait? Need some sage advice here.

I have also installed the spray bar, which forced me to increase my bps due to the increased surface agitation - so I have had to dial in this CO2 again (expected) - and I am almost at the right level where fish do not gasp at all and exhibit no lethargy.

Here is the tank:
1


What are my next steps?

Some ideas that I had:
1) Continue reducing the light until I no longer see algae growth but hopefully I can still push growth. My issue here is that maybe the higher light could force my s.repens to grow more rapidly and as a result shade the plants and outcompete the algae.

2) Leave everything at the CO2 level, the flow from the spray bar, the daily EI dosing, the light that I have it at and see what happens.

3) Trim all of the leaves that have any of that algae, massive water change, then do 2) or 1).

4) Introduce Amano or Bristlenose pleco in tandem with any of the above.

I am just not sure what the best next step will be - please if there is a better idea, share :).

** I am wondering if that thinning that we see on some of the rotala is due to the rapid changes in lighting/flow/CO2 that I made with the spray bar and change to lighting.

Cheers,
Josh
 

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Hi all,
Aquatic plants are nearly all C3 plants
This one has come my way via my "day job", it gives some figure for C3 photosynthesis (about 88% of aquatic plants), bicarbonate usage (about 50%), CAM (about 8%) and C4 (about 4%).

It is an interesting paper on methods of carbon concentration and C4 photosynthesis in Otelia alismoides, <"A look at the leaf anatomy of an unusual freshwater aquatic">, from the abstract.
........Freshwater plants, which evolved from terrestrial ancestors, exchanged water as a limiting factor in their environment for a potential carbon shortage due to low rates of carbon dioxide diffusion into the leaves. Adaptations made to accommodate this limitation include thin cuticles, a lack of stomata and sub-stomatal spaces, and chloroplasts in the epidermal cells. Some freshwater plants also have multiple carbon dioxide-concentrating mechanisms (CCMs), including bicarbonate (used by about 50%), CAM (about 8%), and C4 (about 4%). For plants with multiple CCMs, the switch from one to another can be induced by a change in carbon dioxide concentration, with CAM or C4 kicking in when CO2 is low........
cheers Darrel
 
Hi all,
is anyone else NOT seeing the photos
Any idea on the type of algae on my s. repens?
None for me I'm afraid.

I've looked at the linked address for the image and it points towards a google mail server rather than a file on the WWW or hard drive, so you may need to download the files again and then attach them via the "Upload a File" option at the bottom of the thread.

cheers Darrel
 
Hi everyone,

I have gone back and uploaded the photos!

A quick update: I did get some amanos on order (I had intended on buying some anyways and figured this was a good option in all cases). I also did a large water change to get those algae spores out. I did not trim the leaves because a 24 inch deep tank and my arm with scissors on a tiny plant ... well ... but if you on UKAPS strongly suggest this, then I am in!

The phrase, "focus on growing plants and not beating algae" has been resonating with me more -- and it leans me towards extending the photoperiod (as I think part of the algae bloom itself was TOO high intensity for TOO long -- a lower intensity (higher than compensation point and good enough growth) will allow me to strike the balance easier with CO2 demand and will create the same amount of food.

Nonetheless, I spawned these opportunistic buggers and would like to outcompete them!


Josh
 

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