# Too little light



## Christos Ioannou (25 May 2015)

So far, I have been seeing posts linking too much light with various problems, in a high tech planted tank.
What about *too little light*? What are the effects on the plants? Especially those labeled as medium/high light demand.
No growth? Melting? Interested to know.
Thanks!


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## Julian (25 May 2015)

There's no such thing as a high light plant, merely plants which require more CO2 than others.

As long as CO2 is available, plants will grow with any amount of light (within reason).


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## xim (25 May 2015)

Remember: it is almost illegal to say "too little light" here.

When there is too little light, the plants or some parts of it will just die. And when that happens, the water quality and oxygen level will go south. Harmful bacteria could multiply very quickly and harm your critters. A few years ago I almost lost a breeding colony of my Corydoras from sores. Medication didn't work. The situation improved only when I increased the light.


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## Andy Thurston (25 May 2015)

Julian said:


> There's no such thing as a high light plant, merely plants which require more CO2 than others.
> 
> As long as CO2 is available, plants will grow with any amount of light (within reason).


not strictly true. most plants will grow in lower light conditions. I've struggled with glosso and rotala wallichi at lower light levels both are doing much better under higher lighting, co2 was the same in both lighting conditions
theres also a couple of tank journals on here where the op has been failing until they upped their lighting


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## Tim Harrison (25 May 2015)

There is such a thing at too little light. Different plants have varying requirements. Each has a LCP (light compensation point), below which the plant will fail to grow and eventually die. CO2 can raise the LCP a bit but then the plant is forced to adapt to resource limitation and that is often a costly affair...
This thread is quite informative, and sometimes amusing...http://www.ukaps.org/forum/threads/low-tech-lighting-levels.29004/


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## Christos Ioannou (25 May 2015)

So if a plant dies off due to low light is this something similar to melting that is caused by high light and poor co2? Or is it something visually different? Also is a dying plant prone to algae? Finally would low light be something perceived by the eye or you need a par meter for that?


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## Julian (25 May 2015)

You'd have to be using a candle to kill a plant with not enough light...


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## Christos Ioannou (26 May 2015)

Julian said:


> You'd have to be using a candle to kill a plant with not enough light...



Hi Julian,
definitely don't want to be a jerk, but what made you change your mind from your earlier posts to a similar question


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## sciencefiction (26 May 2015)

Troi said:


> CO2 can raise the LCP a bit but then the plant is forced to adapt to resource limitation and that is often a costly affair...



Yes, CO2 raises the LCP point, hence why CO2 injected tanks can go by with very little light without experiencing the light limitation problems which are very obvious in a non-co2 tank.



Christos Ioannou said:


> Or is it something visually different?



No different than what folks attribute to low CO2, yellowing leggy growth, no growth, melting/browning, the roots especially can become mush, so symptoms can be differ depending on plants and some last longer, some wither fairly quickly within weeks.

I've posted my own few pictures in a couple of threads, Christos(you ) linked one of them above.
But here are others, most are not mine but the bottom are mine.

Glosso limited on light:





This below shows the same glosso actually in the first phase of light deficiency when it starts growing leggy, then if severe, it goes into the state as in the first picture.




An entire fish tank with limited light, dare to say more than a candle can provide but just about..




The same fish tank after enough light was provided for two months.





Dwarf sag under insufficient light:




Valis under insufficient light(see the tips missing which just kept melting and falling off.....)




Valis under more light in the same tank at the same time:






Same fish tank taken from the same area of the tank:


Light unit working:






Light unit failed and doing by 1/3rd of the light from before:





So, can you see the pattern of distruction? The difference is having plants or not having plants especially in a non-co2 tank where there isn't enough CO2 to compensate for the low light levels.


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## Julian (26 May 2015)

Christos Ioannou said:


> Hi Julian,
> definitely don't want to be a jerk, but what made you change your mind from your earlier posts to a similar question


No worries mate. I haven't changed my mind, that post is from a year ago and since then I've learnt that CO2 availability is the main thing. It's really really hard to have slow growth/problems attributed to too little light. If you're using a proper light for your tank, and you still get pale/transparent leafs and slow growth, it will be CO2 availability that is the issue. 

99% of problems on this forum are because of too much light and not enough CO2.


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## Julian (26 May 2015)

Big clown said:


> not strictly true. most plants will grow in lower light conditions. I've struggled with glosso and rotala wallichi at lower light levels both are doing much better under higher lighting, co2 was the same in both lighting conditions
> theres also a couple of tank journals on here where the op has been failing until they upped their lighting


Agreed, there are plants that need more light, but i believe they only require these light levels initially. My experience with glosso (especially in vitro grown) is that it needs a lot to get it started else it will melt. Once its rooted, it can survive on the same light levels as everything else. Not pushing this as fact, this is just what experiences have led me to believe.


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## sciencefiction (26 May 2015)

Julian said:


> My experience with glosso (especially in vitro grown) is that it needs a lot to get it started else it will melt. Once its rooted, it can survive on the same light levels as everything else. Not pushing this as fact, this is just what experiences have led me to believe.



Glosso in my low tech






Oops, same tank on low light, glosso and other plants wipe out on very low light in the space of weeks. I don't know how low you think they can survive on but they can't for too long.


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## Julian (26 May 2015)

sciencefiction said:


> Glosso in my low tech
> 
> 
> 
> ...



If it was only the glosso that died, this would have disproved my belief that it is not a high light plant. But because your other plants died too, it just shows that it is as equally receptive to the same light levels as any other plant.


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## sciencefiction (27 May 2015)

Julian said:


> If it was only the glosso that died, this would have disproved my belief that it is not a high light plant. But because your other plants died too, it just shows that it is as equally receptive to the same light levels as any other plant.



Yes, equally receptive as a lot of other plants. I used to have over 20 species, now I have the common low light tolerant plants most of which except for the anubias,  java fern and crypts,  melted completely before re-growing under lower light(bacopa, ludwiga,  amazon swords and valis totally melted to stumps first and then regrew so seem to be able to adapt)
The point is there's a point when too little light is just too little light to support many common species of plants. From the back of my hand glosso, hydrophila pinnatifida, a few fancy echinodorus and aponogetons, Nuphar japonica,Nymphaea lotus all melted and died completely from quite the size.  There were a few more I can't recall right now that I had in the tank and are also gone for good.


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## Tim Harrison (27 May 2015)

It is interesting...I've found that leaf morphology is often different as the plant regrows to adapt to low light conditions, but not every plant has that adaptive response and instead...well...just dies...


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## Christos Ioannou (27 May 2015)

Thanks for all your feedback! Reason I am asking is that I have 3 cfl @32w hanging 60cm over tank (90cm oversubstrate). Soon I will switch to 2x54w t5 for a more uniform distribution of light (will be able to change hanging height)

As I have a lime green drop checker @ substrate, 1unit ph drop before lights on, and decent flow and surface agitation through a spraybar, I can only but consider my light to be the problem in my setup...


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