# Effects of too little light



## Jaap

Hello

I was wondering what symptoms would one see if the light in your planted aquarium is too little?

Thanks


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## Julian

Slow growth, yellowing/transparent leaves.


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## pepedopolous

If CO2 is the main 'building block' for plant growth and repair, and light is the energy source for this; surely the symptoms would be the same- poor growth, melting...

Despite saying this, CO2 is the most difficult to get right. And since the availability of T5s and LEDs it's all too easy to have too much light.


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## Julian

pepedopolous said:


> If CO2 is the main 'building block' for plant growth and repair, and light is the energy source for this; surely the symptoms would be the same- poor growth, melting...
> 
> Despite saying this, CO2 is the most difficult to get right. And since the availability of T5s and LEDs it's all too easy to have too much light.


Plants can grow with the minimal amount of CO2 e.g what's in the water. Obviously different plants have different requirements so yes, you see similar results but not as severe... You wont get transparent leaves, yellow maybe, which leads to rot, which leads to death.


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## tim

If you turn up the lights and melt/ dying plants continues, you know you have co2 issues ime, once plants suffer this damage they are best removed.


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## parotet

One thing I've noticed lately is that poor light make much more difficult a bushy shape in your plants... But I guess the problem is that talking about low light or high light means really nothing. Light is just one part of the equation and good growth can be achieved with different combinations.

Jordi


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## Jaap

So is there a chance that low light might have the same effects as in a situation of high light and low CO2 or bad distribution?


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## Marcel G

Read these two articles:
1) http://prirodni-akvarium.cz/clanky/CO2, Light and Growth of Aquatic Plants.pdf
2) http://prirodni-akvarium.cz/clanky/CO2 in Planted Aquaria.pdf


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## Julian

Hello mate. I understand how you feel at the moment, I was there once. I promise you if you keep at it, you'll get there eventually. You certainly have a good idea of what you're doing, just keep doing it and those god damn plants will grow eventually!

Please let me know your progress!


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## Jaap

Thanks man very nice articles! One question....how do I know that I am not at or below the light compensation point? Any signs e.g no growth or little growth or melting or no sustainability? 



ardjuna said:


> Read these two articles:
> 1) http://prirodni-akvarium.cz/clanky/CO2, Light and Growth of Aquatic Plants.pdf
> 2) http://prirodni-akvarium.cz/clanky/CO2 in Planted Aquaria.pdf


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## roadmaster

Jaap said:


> Thanks man very nice articles! One question....how do I know that I am not at or below the light compensation point? Any signs e.g no growth or little growth or melting or no sustainability?



I often wondered this as well in my low tech affairs.
I began to look at one or two plants, and noted the frequency with which new leaves appeared and so long as the new growth leaves looked healthy, then ... 
I would actually count the numbers of new leaves on the majority of the plants (over weeks) and so long as new ones were sprouting then I assumed the conditions were at least acceptable for continued growth.


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## Jaap

Ok I know that this has never happened before for someone to have lower light than the required because most of us just go crazy when it comes to lights.....but maybe my plants are melting because of poor light conditions...I mean my pH drops from an 8 to 6.5 and I have a kH of 9....I know my plants are the best indicators but isn't there a chance that my lighting is too little? Come on guys....its not always CO2 the problem....


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## dw1305

Hi all,


roadmaster said:


> I began to look at one or two plants, and noted the frequency with which new leaves appeared and so long as the new growth leaves looked healthy, then ...
> I would actually count the numbers of new leaves on the majority of the plants (over weeks) and so long as new ones were sprouting then I assumed the conditions were at least acceptable for continued growth.


I think that is a pretty good approach.





Jaap said:


> Ok I know that this has never happened before for someone to have lower light than the required


 It does, a lot of non-specialized planted aquarium keepers told me that they can't keep plants and they lose them in the winter. Often they said they could grow Java fern, but everything else died. I'm pretty sure this is attributable to lower ambient light levels in the winter tipping their plants over the edge. 

The LCP of plants wil vary over an order of magnitude, if you have light intensity issues slow growing plants with dark green leaves (_Bolbitis heudelotii, Anubias, Microsorum_ & mosses) are the ones least likely to show symptoms. 

If you use EI you can tell whether it is a light or a CO2 problem by using a floating plant, they have access to aerial CO2 and this takes CO2 out of the equation. It is also recieving the full intensity of the lights.

I choose to use _Limnobium laevigatum_ as my floater for the "Duckweed Index" as it has leaves without hairs etc., that might obscure the leaf colour, and it is more tolerant of low pH/low nutrients than the original Duckweed (_Lemna minor_). 

cheers Darrel


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## clonitza

Jaap, you can test if you have too little light by increasing it  .. go from 30% to 50-60% after the water change and see what happens in a week.


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## Jaap

clonitza said:


> Jaap, you can test if you have too little light by increasing it  .. go from 30% to 50-60% after the water change and see what happens in a week.


Why after a water change?


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## Jaap

dw1305 said:


> Hi all,
> I think that is a pretty good approach. It does, a lot of non-specialized planted aquarium keepers told me that they can't keep plants and they lose them in the winter. Often they said they could grow Java fern, but everything else died. I'm pretty sure this is attributable to lower ambient light levels in the winter tipping their plants over the edge.
> 
> The LCP of plants wil vary over an order of magnitude, if you have light intensity issues slow growing plants with dark green leaves (_Bolbitis heudelotii, Anubias, Microsorum_ & mosses) are the ones least likely to show symptoms.
> 
> If you use EI you can tell whether it is a light or a CO2 problem by using a floating plant, they have access to aerial CO2 and this takes CO2 out of the equation. It is also recieving the full intensity of the lights.
> 
> I choose to use _Limnobium laevigatum_ as my floater for the "Duckweed Index" as it has leaves without hairs etc., that might obscure the leaf colour, and it is more tolerant of low pH/low nutrients than the original Duckweed (_Lemna minor_).
> 
> cheers Darrel


What will you see on the floating plants that will indicate low light?


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## clonitza

It will be less likely to have an algae bloom after a water change if something goes wrong. 
Anyway feel free to experiment but any change you do stick on it for a couple of days to see results.


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## dw1305

Hi all, 





Jaap said:


> What will you see on the floating plants that will indicate low light?


 Leaf death occurring more quickly than leaf growth, pale colour and a dwindling of the leaf rosette, this is known as <"Etiolation">.

At that point you've discounted CO2 (plant has access to atmospheric CO2 at 400ppm) and nutrients (via EI), so that only leaves light. 

If the light intensity (really <"PAR">) doesn't reach <"light compensation point">, increasing the length of the photoperiod won't help, but increasing the PAR will.

If light intensity exceeds LCP, and nutrients, including carbon, are available the plant will show a pretty rapid greening, followed by growth, response.

The situation in a tropical water course would be slightly different from the situation in more temperate latitudes. In the tropics light intensity is very high, and a floating plant would need to be able to deal with very high light levels. Again this is why Amazon Frogbit is useful for the "Duckweed Index", it can grow quite happily over a large range of light intensities without showing light damage (although leaf colour may change and the red marking become more pronounced).  

Here is Amazon Frogbit enjoying itself as an "invasive alien" in S. California (from <http://plants.ifas.ufl.edu/node/740>).







*Why plants scorch*
Plants have evolved in differing environments, and a very dark green plant like _Anubias spp. or Bolbitis heudelotii_, will have evolved in a shady, low light environment. The plant is very dark green because it has a lot of chlorophyll to harvest as many of the scarce passing photons as it can. Producing chlorophyll has a "cost" to the plant, and natural selection via "survival of the fittest" will winnow out those plants carrying genes that produce sub-optimal amounts of chlorophyll (either too much or too little) for the conditions the plant evolved in.

If you place a very dark green plant into intense light for any extended period, Clive's <"photon torpedoes"> will damage them.
*
Why tropical plants are different*
Tropical plants forest plants differ from those from more temperate latitudes in the way recieve the PAR they require. Rather than having continual diffuse light they will get in frequent ephemeral patches of very high intensity light, and areas that don't get any sun-light won't have any vegetation (not enough PAR).





An end result of this is that a plant like an _Anubias_ can adapt to higher light, when it has grown emersed with access to aerial CO2.

This is one of mine that has become emersed, the scorch marks are thermal damage from the leaves being in contact with the light unit (when it had spiral CFL lamps rather than LEDs).





cheers Darrel


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## parotet

Brilliant Darrel....


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## Jaap

I would like to inform everyone that is interested in this thread that the problem was indeed too little light. The effects are not completely similar but are very very close.

If someone has low co2 then you see melting and plenty of it but as soon as you up the co2 all is fine.

If someone has too little light then you see no growth and very little melting as well as pale plants or dark leaved plants due to the high amounts of chlorophyll they produce to utilise the very little light given to them.

The effects are similar and can be mixed up but I believe someone with more experience than I have could have caught that earlier and easier than I did.


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## Jaap

Purely for educational reasons, I would like to inform anyone else that stumbles upon this thread, that the GroBeam 600 was set at 30% and 50cm from the substrate at the beginning. This caused the plants not to grow and at some point melt. After inspecting all other possibilities I was left with no other choice but to increase the light intensity and i gradually did, reaching 100% intensity. Now I am lowering the light fixture by 5cm and I am at 45cm from the substrate. I will stop lowering it as soon as I see healthy plant growth.

Thanks


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## Mr. Teapot

Very similar experience with the same light and same tank size when I started. The only plants just about growing(ish) were anubias and crypts. I've ended up with a Grobeam 1500 @ 100%*. Very happy with the health of my plants as a result of the increased light level.

(*I'm not recommending anyone else use this amount of light as a benchmark or magic formula on their own tank - it just worked for me)


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## sciencefiction

Different plants need a different amou


Jaap said:


> Hello
> 
> I was wondering what symptoms would one see if the light in your planted aquarium is too little?
> 
> Thanks




There's a limit when certain plants just don't survive with the amount of light given, don't grow, intermittently melt and eventually die, which can take,  depending on the species, from weeks to months. And there's a limit when they do grow but they are literally disfigured, grow in an unhealthy shape, smaller leaves, loss of colour, dropping bottom leaves, and again melting, etc.. Which I think is called "leggy" growth. So light is not the enemy. It is imperative that, depending on species, they get their deserved share.

Honestly, just do your thing, experiment  the way you like and form your own opinion because this hobby has turned out to be a political science, or some sort of fashion.


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## Tim Harrison

Interesting thread, and dare I say it...an informative one too It seems that the causal effects of too little light are often over shadowed by those to do with CO2, flow, and distribution. 
And also just for the sake of contention I also like SF's final line above; especially the comment regards political science...


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## Andy Thurston

Troi said:


> Interesting thread, and dare I say it...an informative one too It seems that the causal effects of too little light are often over shadowed by those to do with CO2, flow, and distribution.
> And also just for the sake of contention I also like SF's final line above; especially the comment regards political science...


Me too
Theres still not too much info on par and leds. I seem to remember telling jaap to start at 30% power 10cm from the water. I guess that puts my guess somewhere in the ball park.
Im not disputing clives methods but sometimes i feel he misses the fact that some peoples lighting is already quite low and always recommends it be lowered further. I lowered the lighting in the cube and some of the plants suffered.
Which leads nicely back to...


> Honestly, just do your thing, experiment the way you like and form your own opinion because this hobby has turned out to be a political science, or some sort of fashion.


We learn from our mistakes, so the more mistakes we make the better we become


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## dw1305

Hi all, 
It will depend a little bit how much natural light your tanks get, but particularly if they are open topped, ambient light is going to play a part in plant growth in most situations. 

Sun-light is incredibly bright, even in the shade on a bright day in the summer you are getting about 10,000 lux in the shade, 60,000 lux in the sun, and as you approach the equator potentially at least double that . 

You can compare this with room lighting, where 500 lux is quite a brightly lit room, and bright moonlight is about 1 lux.

Because I always have "jungles",  I do very little intervention in terms of pruning etc., and my tanks are fairly nutrient poor, the amount of plant growth I have gives a measure of the amount of PAR.  

At the moment my 2 x 2' tanks both have 2 x 24W T5 fittings, so reasonably high light  in a "no added CO2/low nutrient" situation. The only regular pruning activities I do are to remove dead leaves and thin out the floaters. 

If I don't thin out the floaters  in the autumn (from approx. 3/4 coverage down to ~ 1/3) the planted plants will begin to undergo leaf death,  because leaves that are now below light compensation point will be shed.  This process will continue through the darker months, with I'd estimate tank plant biomass  about  1/3 lower in the winter than the summer.

cheers Darrel


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## roadmaster

Jaap said:


> I would like to inform everyone that is interested in this thread that the problem was indeed too little light. The effects are not completely similar but are very very close.
> 
> If someone has low co2 then you see melting and plenty of it but as soon as you up the co2 all is fine.
> 
> If someone has too little light then you see no growth and very little melting as well as pale plants or dark leaved plants due to the high amounts of chlorophyll they produce to utilise the very little light given to them.
> 
> The effects are similar and can be mixed up but I believe someone with more experience than I have could have caught that earlier and easier than I did.



Maybe someone would have caught it earlier if mention was made earlier of the lighting/PAR or type of fixture.
Questions were more regarding symptoms of inadequate light rather than description of the lighting being used.
Was not until the end of this thread that mention was made of particular fixture.


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## parotet

roadmaster said:


> Maybe someone would have caught it earlier if mention was made earlier of the lighting/PAR or type of fixture.


IMO we are still far away from standard reference values for LED lighting (due probably to different LED types used, number of LEDs in the fixture, lenses used, few PAR readings, etc.)... and this is a problem for the hobbyist. In other words, although we know "watts per liter/gallon" is not an accurate reference, it is indeed a rule of thumb that let you know in which level of lighting you are. A quick search on the internet would be enough for the newbie to know if his/her T8, T5HO or metal halide lighting is low, medium or high. Additionally this light level is in our minds linked to a kind of setup (C enriched tank, non enriched, need of intensive fertilization, etc.). The only variation in this interpretation is the number of units and distance from bulb to bottom. Most of us don't own a PAR meter and we are still able to understand what we have or what we buy. Unfortunately, with LED fixtures there are other parameters with a huge influence on the light output: type of LED, lenses, if it is dimmed, distribution of LED, etc. and the difference of any of these combinations seems enormous to be able to provide a rule of thumb. For this reason it really amazes me that most of light suppliers (lots of them very well known ones, not just chinese) do NOT inform about PAR readings of their fixtures... isn't it incredible? They sell lights! Imagine you are a car seller and you wouldn't inform your customers about the power of the car  You'd just say "Yes, it goes fast, and it is red ... Pardon? The power? I will ask the factory engineers, but... look the seats are very comfortable!"

I miss a kind of calculator asking the user basic things such as nº of leds, type of leds, consumption, if there are lenses, aquarium depth, etc. to give just a rough feedback saying "you have high light, you'd better provide a source of C and ensure good filtering"

Jordi


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## GreenNeedle

The reason they don't put out PAR readings is because that is a measurement at source.  They have no way of knowing where your source is or what barriers there are.

i.e. if they said PAR without lenses @ 3ft = 150 we would then need to know what about 2ft, 1.5ft, 1ft.  What about with 10,20,30,45,60,90,120 degree lenses.  What about through water etc.

They give you lumens because that is a measure of the output of the lamp, not a measure of light received at a set distance but the amount of visible light it is outputting (or at least is supposed to be outputting)

A long time ago I wrote about LED comparisons to the WPG and this was based on the cheapo luxeon copies from china ebay sellers.  If the WPG rule is based on T8 W=1WPG then:
T5HO = 1.2WPG
T5NO = 1.3WPG
LED=1.5WPG

I would suggest when you are using top quality LEDs that it would be higher but I have no growing problems using 0.5WPG of cheapo LEDs over non CO2 tanks apart from leggy stems whereas with T8 I would need to be getting closer to the 1WPG area.

Its crude its basic but it won't be that far off.


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## Tim Harrison

dw1305 said:


> Hi all,
> It will depend a little bit how much natural light your tanks get, but particularly if they are open topped, ambient light is going to play a part in plant growth in most situations.
> 
> Sun-light is incredibly bright, even in the shade on a bright day in the summer you are getting about 10,000 lux in the shade, 60,000 lux in the sun, and as you approach the equator potentially at least double that .
> 
> You can compare this with room lighting, where 500 lux is quite a brightly lit room, and bright moonlight is about 1 lux.
> 
> Because I always have "jungles",  I do very little intervention in terms of pruning etc., and my tanks are fairly nutrient poor, the amount of plant growth I have gives a measure of the amount of PAR.
> 
> At the moment my 2 x 2' tanks both have 2 x 24W T5 fittings, so reasonably high light  in a "no added CO2/low nutrient" situation. The only regular pruning activities I do are to remove dead leaves and thin out the floaters.
> 
> If I don't thin out the floaters  in the autumn (from approx. 3/4 coverage down to ~ 1/3) the planted plants will begin to undergo leaf death,  because leaves that are now below light compensation point will be shed.  This process will continue through the darker months, with I'd estimate tank plant biomass  about  1/3 lower in the winter than the summer.
> 
> cheers Darrel


That's a heck of a lot of light, I did something similar a while back (2x24W T5) it worked surprisingly well, I got amazing growth rates, for a low-energy. No fertz, just soil, so most of the nutrients were in the substrate feeding big root feeders, but after 3 months or so I found different types of algae creeping in...but it was nothing unmanageable.

The observation about ambient light and biomass/growth is interesting...I've always thought that it's this that forms the basis for Diana Walstad's theory regarding the siesta period, which has come under a lot of criticism...

In the case of my tank there is probably enough ambient daylight to maintain photosynthesis during the siesta period - especially since it has an open top - all be it at a slower rate and perhaps somewhere around the compensation point. So it's not necessarily a costly stop-start process. 

So under those circumstances perhaps the siesta period gives plants the long day length they require, whilst allowing CO2 regeneration - so when the light comes back on plants can photosynthesise more effectively and efficiently. 

With regards the inhibition of algae, again in a low-energy tank, I suppose the theory is based on the supposition that algae is more efficient at taking up CO2. Therefore, algae gains an advantage over higher plants when CO2 concentration drops during the afternoon. Once again, the siesta period supposedly redresses this problem by allowing CO2 regeneration.


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## parotet

SuperColey1 said:


> The reason they don't put out PAR readings is because that is a measurement at source. They have no way of knowing where your source is or what barriers there are.
> i.e. if they said PAR without lenses @ 3ft = 150 we would then need to know what about 2ft, 1.5ft, 1ft. What about with 10,20,30,45,60,90,120 degree lenses. What about through water etc.


Yes, I agree it is much more complex than just giving a number, but I am sure there are other ways of showing this information... For example: http://www.prirodni-akvarium.cz/en/index.php?id=en_measurement
Some reference underwater readings (without water it makes no sense for aquarium), for the standard size of tank for which the fixture is built, with the lenses used in the fixture you are buying and at 4-5 depths should be more than enough.
Afterwards if the customer decides to put a lid, has a deeper tank, wants to put the light higher or dim it... well, he/she should know the PAR value will be lower.

Maybe another reason for not communicating this is because most of the customers really don't care about what they are buying. You know, outside this one and a limited number of forums and websites, statements like "the more light the better", "the right spectrum for growing plants" and other similar ones are still prevalent. So suppliers just keep saying "look it is red and seats are comfortable"

Jordi


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## GreenNeedle

There are articles about ambient light out of the photoperiod interfering with nature.  I read one that said that any light outside of the photoperiod that gets to the plants can interfere with the way the plants grow.  i.e. don't get a proper rest at night.

I read a recent article the other day that was talking about modern humans moods being affected by them not getting proper full darkness during their sleep due to outside lighting coming through curtains even saying you shouldn't charge your phone or have illuminated clock radios next to your bed.



parotet said:


> Maybe another reason for not communicating this is because most of the customers really don't care about what they are buying. You know, outside this one and a limited number of forums and websites, statements like "the more light the better", "the right spectrum for growing plants" and other similar ones are still prevalent. So suppliers just keep saying "look it is red and seats are comfortable"



That is the main reason Jordi.  You answered your own question.  Same as electrical manufacturers that are inventing things to make statements about their new product..i.e. TVs so that they can suggest you need it.

Similarly you should only use T5HO if you are wanting to utilise space saving.  The same amount of watts in a T5NO give out more light and are more efficient.  You need more tubes to get that wattage but you will get more light for the watts.  i.e. If you have 2 T5HO tubes that total 50W You would need roughly 3 T5NO tubes to get to 50W but you would have more output in terms of light for the same wattage.  That doesn't sell high end T5HO units though and people became (and still are to a degree) obsessed with the HO part.  It is only really relevant for space saving when you needs loads of tubes.


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## Tim Harrison

Yep I think it's been well known for some time. As an example, fighter pilots on night duty perform significantly better if they sleep in total blackout conditions during the day...


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## dw1305

Hi all,





Troi said:


> The observation about ambient light and biomass/growth is interesting...I've always thought that it's this that forms the basis for Diana Walstad's theory regarding the siesta period, which has come under a lot of criticism...


 I have the tanks all on a 12 hour day. When I set them up originally I did have a siesta period, so they came on about 07:00 and went off at 21:00 with a 2 hour siesta around midday. Eventually I decided the siesta didn't make any difference, so now they are on from 07:30 to 19:30. 





Troi said:


> In the case of my tank there is probably enough ambient daylight to maintain photosynthesis during the siesta period


 It definitely would in the tanks in the lab., and probably the ones in my kitchen. 

I'm not too concerned about having "_too much_" light, I'm not interested in aquascaping etc. so for me more light intensity just equals more plants. 

cheers Darrel


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## sciencefiction

I showed some of these pictures before I've taken of my plants. My 5f tank is very diverse in light amount due to the emersed plants so see how some of the same species cope under different lights.

Ludwiga in a well lit area of the same tank:



 


And can you see the ludwiga stalk in the middle, next to the anubias? Lack of growth it's not its only problem I am afraid, and it was planted a few weeks before the above ludwiga but just gets very little light in there.


 


And these two pictures I actually posted last year. First one healthy aponogeton grown in a well lit area of the same tank:


 


Second aponogeton, grown in a shaded area, thiner and brittle leaves, with melting blotches. Wish I had taken a better picture but those two were the longest leaves of the plant I could pull out of the water for the picture at the same water level as the above picture, both pics taken a minute apart.  The two aponogetons on these pictures were planted just 30cm apart in the same tank on the exact same day, from the same pot.


 

I've got some more but it the thread will get clogged


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## 13r0wn7

My lights are as follows:
48x3w crees
Channel 1 16x3w 6400k Cree
Channel 2 16x3w 10k care
Channel 3 13x3w 300-450 cree
Channel 4 3x3w moonlight Cree.

I previously had channel 1 on 40%
2 - 20%
3 - 10%
4 - off 
This was ok then had a boom of bba.. 

Then I turned them down even lower and now all my pogostoman has died and read plants look like there dieing.
All that's ok is a stem plant not sure of its name and my tennulus looks ok to.

Could this be because of Not enough light?

I am fairly sure I have more then enough co2 in my tank. Dc yellowish and I have a good ph drop for lights on.


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