# Low tech lighting levels



## Graham1984 (28 Aug 2013)

I have an 300L aquaone tank, (120x46x70cm)

I also have a twin 54w T5ho starter, and  the stock 36w t8 starter, (that came with the tank)

I can use one, both or a combination of the two...

Im going to be using a soil substrate, capped with bonsai soil.

I dont have, and probably cant get injected co2, (wasnt looking to go down that road)

I do have a selection of liquid ferts, including easy carbo, but i know that will get expensive for my size tank

Now my questions,...
What kind of light combination should I go for?
What level of light should I go for to keep maintenece to a minimum?
Im aiming for 6 to 7 hours a day, is that correct for a new start up?

Now for what im looking to grow..

your run of the mill crypts, swords, maybe some repens, possibly some java moss, vallis

Im wanting the set up to last, without loads of time spent, im happy to let it grow, jungle style.

Thank you in advance,


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## ceg4048 (28 Aug 2013)

Hello,
		 All of that can be accomplished if you avoid using the T5. It's that simple. The less light you use the less maintenance you will need.

Cheers,


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## Graham1984 (28 Aug 2013)

so if I go with the t8s for 6 to 7 hours a day, with no co2,
or will i need to lengthen the photo period with the lower light?

I wont be swamped with algea, providing i look after things, water wise.

and things will grow, (at some rate) and in 3 to 6 months, with re planting of cuttings and such, Its possible to get a jungle style tank.


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## Michael W (28 Aug 2013)

Why would you want to lengthen the photo period? Wouldn't that contradict to not having high light by avoiding T5s? Going to low tech will grow plants but as a compromise you will have slower growth rate but in return less maintenance. But this does not mean you won't achieve the jungle affect, it just takes time compared to the high tech route which require high maintenance.


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## Graham1984 (28 Aug 2013)

well, the t5hos is too powerful, full stop by the sounds of it..
i was just a bit concerned that the t8s are not strong enough,  ( ive had them on before and not much grew)  (but that may be down to other things)

so, by fools logic, a weak light a little bit longer, should in theory be better than a blast of an overpowered light.
example, the t5s should be able to blast light right down to substrate level. (but too much)

t8s may not be able to get as much down to sub level.. so giving the lower growing plants a bit longer with the lower level of light might be worth while.? or maybe not?


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## foxfish (28 Aug 2013)

The point is... it is the C02 that grows plants & not the amount of light!
So you try  to match the light to the available C02... in a low tech tank there is very little  C02


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## Graham1984 (28 Aug 2013)

Is under lighting a tank not a risk? or possible? or would things just grow so slow you would not be able to tell that anything was happening.


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## Graham1984 (28 Aug 2013)

would increasing circulation of the co2 already in the tank be worth while? (via deep mounted power heads)  or would keeping circulation to a minimum be the best route?

and what about water movement on the surface? high or low?


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## Michael W (28 Aug 2013)

Graham1984 said:


> Is under lighting a tank not a risk? or possible? or would things just grow so slow you would not be able to tell that anything was happening.


 

If anything having too much light is usually the main factor in causing most of the problems. Having high lights or long period of the lighting on will drive the plants to get more CO2 and nutrients. Having lower light levels therefore lowers the plant's need for the CO2 and nutrients.

If you are running CO2 a good flow will allow CO2 to be distributed to plants. Too high of a flow will damage plants therefore making them invest in repairing mechanical damage. However, a side from injecting CO2, your soil substrate will also supply carbon to the plants. The more surface movements the more CO2 will be lost, its usually suggested to keep the surface movement enough to avoid bio films being build up.


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## Aseph (29 Aug 2013)

Graham1984 said:


> Is under lighting a tank not a risk? or possible? or would things just grow so slow you would not be able to tell that anything was happening.


 
it is possible and its a risk, but compared to over lighting is much less stressful and easily remedied. under light means u have very slow growth or no growth at all, the amount of energy produced by photosynthesis if it produced is not sufficient to support plant life, then your plants will slowly wither away.

for comparison my tank is 80cm wide 60 tall, and 40 deep, i m using 2 T5ho 60 cm 2x24 watt mounted 20 cm above tank, with my current setup shades from taller plants and all i m getting around  10-20 umol(low light) at substrate,  40-60 umol mid tank(med light), and over 100 near the water surface.

I m dosing liquid carbon and EI for ferts, it does get expensive if you buy ready mixed product, if possible i suggest getting co2 injection its so much cheaper and so much easier.


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## ceg4048 (29 Aug 2013)

Graham1984 said:


> Is under lighting a tank not a risk?


No.




Graham1984 said:


> or possible? or would things just grow so slow you would not be able to tell that anything was happening.


The more you worry about this, the more problems you will have. I have never seen a tank suffering from under-lighting...ever..unless the hobbyist forgets to turn the light on.

Cheers,


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## dw1305 (29 Aug 2013)

Hi all,


Graham1984 said:


> Is under lighting a tank not a risk? or possible? or would things just grow so slow you would not be able to tell that anything was happening.


What we call low tech plants are really plants that have low potential growth rates in lower light conditions. Each individual plant species will have a "light compensation point" (LCP), where the amount of incident PAR means that production exceeds consumption <Compensation point - Wikipedia, the free encyclopedia>, if light levels don't reach the LCP point death is inevitable.

Once the utilizable light energy exceeds the LCP point growth will occur, as long as all the other nutrients required for growth are available.We don't have LCP values for most aquatic plants, but we can assume that slow growing plants (_Anubias_ spp. for example), mosses and ferns, possessing very dark green leaves (lots of chlorophyll), will have low LCP values, and probably come from low nutrient situations. Other lighter green plants, with much faster potential growth rates, will come from more light and nutrient rich environments, and in many cases are really marsh plants or emergents, that can survive under water, but are really waiting to grow emersed.

Have a look at these threads fr some more information: <Slow growing plants and feeding | UK Aquatic Plant Society> & <Slow growing plants and feeding | UK Aquatic Plant Society>

cheers Darrel


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## sciencefiction (29 Aug 2013)

Graham1984 said:


> Is under lighting a tank not a risk? or possible? or would things just grow so slow you would not be able to tell that anything was happening.


 
Well, to put my 2cents, there is some if you go way too low and there's overshadowing later on. Some plants just won't grow properly then.  For example I've got emersed plants that are casting quite a shadow on the left side of the tank. The plants there not only barely grow, but they grow thin and leggy. So the tank looks empty on that side.  Just close to them, under the same flow distribution of the same filter, but more light they grow a lot healthier and nicer looking.

For example on the below picture of my tank the affected side is the left side. It's not very visible on the picture but there are for example two aponogeton crispus plants I planted at the same time. One is in the middle behind the 3 amazon swords and one is to the very left under the emersed plants(the tallest green few strands in the corner) The difference between the two aponogetons is enourmous. The one in the middle has huge and wide healthy leaves almost reaching the surface, it flowered 2 times in 2 months. The one to the left has very thin leggy leaves. You can also see the difference of the size of vallis as well at the back. It has similar effect to the lower plants.






And here is a cropped picture where you can see the two aponogetons better. It's a bit bushy in the middle but you can see the big curly leaves of the aponogeton in the middle behind the amazon swords and ludwiga and the aponogeton on the left with the thin green leaves


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## ceg4048 (29 Aug 2013)

Your plants are growing thin and leggy because the same plants that are blocking the light are also blocking flow. Blocked flow means blocked breathing as well as blocked ejection of hormones that trigger thin and leggy growth, and that's why the other plants suffer. The configuration shown above is not a good way of confirming your theory because there are multiple direct and indirect effects which you have failed to consider. To test your theory you must eliminate the multiple effects caused by the blockages. Then you will see that the plants respond to lowered light intensity by simply reducing their growth rates, providing that flow and distribution are addressed.

Cheers,


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## Aseph (29 Aug 2013)

ceg4048 said:


> No.
> 
> 
> 
> ...


 
I am a fan of low light tank, but clive what you said is a very strong view, like mentioned before how about not passing a LCP , the plants will wither and in a way thats a problem, I haven't tried this but even with good flow a carpet plants that only getting less than 20umol wont make it i think


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## sciencefiction (29 Aug 2013)

> Your plants are growing thin and leggy because the same plants that are blocking the light are also blocking flow


 

Ceg, the plants that are blocking the light are the tropical emersed plants outside the tank. How the hell are they blocking the flow if they are not inside the tank?
Look at the picture again to see what I am trying to say. In my case if there's a flow blockage, it would block the healthy aponogeton first because it's behind a mass of plants(amazon swords, ludwiga compared to the leggy aponogeton to the left. The current flow makes those plants in the corner wave all the time and the healthy aponogeton barely moves because of the amazon swords and ludwiga in front of it. So healthy aponogeton-less flow, more light. Leggy aponogeton-more flow, less light.


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## ceg4048 (29 Aug 2013)

Aseph said:


> I am a fan of low light tank, but clive what you said is a very strong view, like mentioned before how about not passing a LCP , the plants will wither and in a way thats a problem, I haven't tried this but even with good flow a carpet plants that only getting less than 20umol wont make it i think


That's correct, if the particular plant is seeing energy levels below LCP the plant will wither and die. You can grow carpet plants with very low PAR as long as it is above LCP. It has not been established that 20 micromoles is below LCP for any carpet plant. Do not assume any value unless it has been demonstrated and unless you can account for and control all factors related to health and growth. Carpet plants have been grown with PAR at or below 30 umole, but they grow very slowly. There is no relationship between PAR and plant health. When people have plant health issues they look for the easiest explanation. That usually involves the question of whether there is not enough light. That's why there are so many problems.



sciencefiction said:


> Ceg, the plants that are blocking the light are the tropical emersed plants outside the tank. How the hell are they blocking the flow if they are not inside the tank?


If you want to test your theory, put the plants in question in their own tank and reproduce the PAR value that you currently have. You cannot just pick your favorite excuse for poor performance by assuming the most popular conjecture. As I mentioned, when there is a plant health issue there are often multiple faults which combine to produce the effects. We have to untangle the mess before drawing a conclusion. First, start with known facts. If those stringy plants are growing at all then the light energy being received MUST be above LCP.

The OP's focus is on the popular notion regarding whether he has sufficient light and this is the single worst mistake he can make. There is no point making excuses to use more light. When Darrel points out that slow growing plants have a lower LCP, that number can easily be less than 10 umoles. The LCP for faster growing plants is NOT 5X higher, for example.

The mechanism of leggy growth is explained in the thread Xmas Moss growing "leggy" | UK Aquatic Plant Society

Cheers,


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## sciencefiction (29 Aug 2013)

> You cannot just pick your favorite excuse for poor performance by assuming the most popular conjecture.


 
I am totally not picking my favourite excuse but you just don't want to be contradicted, even with facts. I don't even know if those plants are growing in the corner because all the growth they did was before I put the emersed plants above that side of the tank and before they grew so bushy. I had to move some tall bacopa cuttings from the middle of the tank to the left to make that side look fuller as the tank looked like someone had used the lawn mower there. The large species of plants planted in there besides the aponogeton crispus are crinum calamistratum, Echinodorus rose and Echinodorus gabrielii. You can't even see them on the picture because they are staying the way they were a few months ago. They've no growth compared to the amazon swords which exploded in the middle.  If I had room to put the emersed plants somewhere else I would have long time because I can't get that side to fill up at all and I've been trimming the rest of the tank weekly.



> If you want to test your theory, put the plants in question in their own tank and reproduce the PAR value that you currently have.


 
If I do that and I get those plants to grow, which they will, you'll tell me that the new tank has different CO2, flow distribution levels and I can't compare....
But what I can do is move the emersed plants or at least two of them out of there somehow to let more light reach those plants below. I would have done that right now somehow so I can prove as I am certain that's the issue, but my tank developed a leak a couple of days ago and I've lowered the water level, and I need to deal with that first.


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## Tim Harrison (29 Aug 2013)

So let me get this straight, if energy levels are lower than a plants LCP it will wither and die...yet there is no relationship between PAR and plant health...I may be hard of understanding but it seems a bit contradictory?

If I follow the logic so far I'm left scratching my head trying to figure out why when I went form low light to high light over the same scape with the same flow, fertz, and relative CO2 the increase in general plant growth and health was so perceptible - especially for carpet plants? For instance, glosso that had grown slowly and leggy suddenly grew like wildfire and hugged the substrate forming dense clumps where previously there had only been a few forlorn shoots.

Maybe there is something fundamental that I'm missing - or could it be that...in the best tradition of Occam's razor...light is of greater importance than it's currently fashionable to give credit for?


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## hotweldfire (29 Aug 2013)

ceg4048 said:


> No.
> 
> 
> 
> ...



Err, hang on a minute. On the face of it, this is just wrong. 

However, perhaps we're not understanding you properly. Are you saying unhealthy growth can never be about poor lighting because if there is enough light for any growth there is, by definition, enough light for healthy growth? 

Therefore the poor plant health has to be about nutrient deficiencies (including co2) which will be down to dosing/flow?

I am not a biologist so cannot judge whether you've got this wrong. However, like the OP, my own experience would suggest that you are wrong. For example I have, primarily on the basis of advice from the EI orthodoxy, removed the reflectors from my t8s some months ago. I did seriously reduce the algae in my tank but also ended up with stems at the back showing yellowing growth and melt near the substrate (but looking healthy up top). These stems were healthy prior to removal of said reflector.

I replaced the reflector on the back tube a few weeks ago and eureka! the plants are looking healthy again. Same plants, same dosing, same flow. Is that enough of a controlled experiment?

I would also suggest we all look at our gardens. I have noted some plants that are growing in shade look distinctly unhealthy whereas others in light look healthy. Not the same species so not an RCT but, still, I can't imagine the nutrient levels are different in two bits of my garden. If the difference between the plants was speed of growth I would say you are right. But it is differences in plant health I'm noticing.

Happy to be proved wrong with some scientific evidence. A peer reviewed paper perhaps or a solid textbook. Otherwise I will have to trust my own eyes over your opinions on the matter. I think that constitutes an evidence based approach.

Sent from my iPad using Tapatalk HD


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## Andy Thurston (29 Aug 2013)

Look at my step by step in my signature. there are photos of hc that were in the propagator before i restarted it and i believe that the yellowing of the lower parts of the plant was caused by the shade from the top half of the plant there were no other factors that it could have been. Each plant has different minimum light requirements so potentially not enough light could be a problem.


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## foxfish (29 Aug 2013)

However that was an interesting post that George put on the London aquarium thread!


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## Tim Harrison (29 Aug 2013)

Crypts truly are amazing plants...they always seem to do well. Mine thrive in low light, soil, and hard water. Anyway, I think that part of the problem - in general - and to the point, regarding plant growth and lighting levels, is that so much of our experience is anecdotal and unquantifiable, and whilst this is often OK it's sometimes easy to overlook or exaggerate certain factors to fit perceived outcomes...And I think it's something we are all guilty of at sometime or other...and ultimately it can be confusing or lead to the wrong conclusions - philosophically speaking


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## sciencefiction (29 Aug 2013)

foxfish said:


> However that was an interesting post that George put on the London aquarium thread!


 
Is that about the crypt that grew in his garage in 99% unlit and unpowered tank? This only goes to show that a particular species of crypt can grow in very low light. One may claim crypts don't need CO2 either in that case. ....But how about the overall health of the plant and it's leaf structure? I literary planted two aponogeton bulbs at the same time,  under the same spraybar inside the same tank but two different light levels, one is looking like it's fighting for its life, the other is healthy and growing as it should. Ceg is claiming that the poor unhealthy growth of one of them is because it has less CO2 in there, compared to it's brother about 30 cm apart who is under the same spraybar(working fine and not blocked) but has more light. It's worth saying that neither is melting and has holes or any other damage indicating CO2 issues and the tank hasn't had any algae issues since setup, besides diatoms at the start. The water level is down due to the tank leaking but I just took a couple of picture of the leaves of the two aponogetons outside the water.

Low light aponogeton:






These were the two longest leaves I could take out of the water. Please excuse the fingers.





Higher light aponogeton:


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## Michael W (29 Aug 2013)

I have a question regarding the growth of my ludwigia repens in my low tech tank. It's situation is fairly similar to this topic so I won't most a new thread. I had trimmed one of the stems down since switching substrates. The stem I replanted was around 10cm tall and the left over stem had only two leaves on it which are the emersed form. Since I thought the two leaves were pretty healthy, I decided to leave it in the tank until it fully degrades hoping in the mean time it will send new growth in the form of submerged leaves. This surprisingly worked out quite well. Now the strange thing is both the stems were planted in different locations, the emersed was right next to the spray bar having a lot of flow and the other was at an area with little to no flow, the stem next to the spray bar has since shown around 5cm worth of growth and yet the other around 2cm. I found this quite strange since the replanted stem had so many leaves yet it grew slower than the other stem which still has its emersed leaves along with the new growth. What does this tell me? Does it mean really mean flow is THAT important? I have knowledge from reading posts and offer what I have gained from the posts but lack first hand experience to back it up. So the answer to this will give me a bigger confidence boost to my knowledge or improve it and give me an example which i can share.


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## sciencefiction (29 Aug 2013)

By the way, here is a picture of the tank from a few months ago. It was soon after I put the emersed plants on that side. You can see on the picture the aponogeton on the left has not grown one bit since if you compare the before and after pictures. That's the advantage of taking a lot of pictures. Compare to the aponogeton behind the amazon swords and ludwiga on which you can see the tips only at that stage. So they were still the same size at that point. However shading one of them has made the difference in appearance and size.


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## Michael W (29 Aug 2013)

I found this article on tropica's website which may help in this discussion too. Hope it will be of use as a reference.

Tropica Aquarium Plants - Rådgivning - Tekniske artikler - Vandplanters biologi - Interaktioner mellem lys og CO2


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## sciencefiction (29 Aug 2013)

And I am sorry to hijack the thread so much but I found a video too and dug up my dates. I've put the emersed plants on the 19th of May. The video below is from just over two weeks after that. You can see the growth of the two aponogetons up to that point. They are shown between 0:10 and 0:30 seconds at the start of the video. Bothe are the same size at that stage. There's been no change in flow setup at all and if anything was overgrown since that could have blocked flow and CO2(in a non-CO2 tank by the way), then it would have been the healthy aponogeton in the middle because the amazon swords, vallis and ludwiga took off.

watch between 0:10 and 0:30sec.


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## Ady34 (29 Aug 2013)

Michael W said:


> I found this article on tropica's website which may help in this discussion too. Hope it will be of use as a reference.
> 
> Tropica Aquarium Plants - Rådgivning - Tekniske artikler - Vandplanters biologi - Interaktioner mellem lys og CO2


was just about to post that very same article  Tom Barr presented it here not long back and it was very interesting.
Low light and low c02 is the worst case scenario yielding little growth. High light and low c02 yields more growth (plant mass), but low light and high c02 yields double the mass gained (both high light and high c02 obviously create the biggest gains). Light definitely plays a role, and is the accelerator, but c02 is the go go juice without which you wouldnt be able to grow fast without conking out!! The article is much more detailed regards the plants growth mechanisms which is worth understanding before too many conclusions are drawn.....too much light obviously negates the positive effects and leads to melt. What is meant by high light is also slightly vague in this instance, perhaps it is just a little more than the lcp? I imagine that the effects, tolerances and success levels vary from species to species also.
Taken from that article:
"Table 1 shows the results of these experiments expressing the growth rate of Riccia fluitans in percent per day, while assuming exponential growth over the period (1). We see that at low light and low CO2 Riccia fluitans is barely able to maintain a positive growth rate whereas at low CO2 and high light the growth rate is almost 6 fold higher. More importantly, at low light levels the addition of CO2 is able to stimulate the growth by a factor of almost 4!
Maybe a stimulation of the growth rate by a factor of 4 to 6 does not seem much but because of the exponential nature of the growth rate it really makes a difference over a period of, for example, two weeks. Figure 3 shows how 1gram of Riccia fluitans develops over two weeks with four different growth rates. Low light and low CO2 barely result in positive growth over the two weeks, whereas the treatment with high CO2 and low light translate into almost a doubling of the tissue weight. For comparison, the high light and low CO2 result in 2.5 gram of tissue after two weeks. It is needless to say, that the benefit from increasing both light and CO2 surpass the effect of raising only one parameter. At the highest light and CO2 availability, 1 gram of Riccia grows into astonishing 6.9 gram after two weeks. Surprisingly, the stimulation observed on the growth rate when both light and CO2 are increased is larger than the additive contribution from each individual parameter. Example: The growth rate at low light and low CO2 is 1.1% per day. By increasing light, the plant grows 3.3% per day or an additional 2.2% compared to the starting condition. Similarly, by increasing CO2 the growth rate is now 3.8% per day or an additional 2.7%. An additive relationship would then translate into 6.0% per day (1.1 + 2.2 + 2.7) but the resulting growth rate from combining light and CO2 is 9.2% per day, which is significantly larger. This tendency also holds when moving even higher up in light and CO2"

In a low tech tank it can be expected that c02 levels are low, in the same tank in the shade, both light and c02 will be low so growth will be much reduced which is likely what you are experiencing sciencefiction. Clive isnt wrong as more c02/ferts will yield better growth, but i suspect in your particular low tech tank that light may be the limiting factor.
Cheerio,
Ady.


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## hotweldfire (29 Aug 2013)

Michael W said:


> I found this article on tropica's website which may help in this discussion too. Hope it will be of use as a reference.
> 
> Tropica Aquarium Plants - Rådgivning - Tekniske artikler - Vandplanters biologi - Interaktioner mellem lys og CO2


 

This is a really useful page. Effectively what the tropica experiment shows is that both light and co2 affect plant growth. So it is not the case that you cannot underlight an aquarium. For example they state

Both fluorescent light and highpressure-quicksilver lamps may produce sufficient light if supplied with effective reflectors but in deep aquaria (more than 50 cm) is very difficult to offer enough light to small light demanding foreground plants.

At the same time they state 

Based on our experiments, we suggest commencing CO2 addition before any other action is taken! 

Crucially light and co2 interact to affect plant growth. I remember a1matt once writing on this forum that in his low light tanks he used to run a tiny amount of injected co2 and found the plants did better than without it. At the time I thought "what's the point of that"? The answer is that a bit of co2 allows the plants to use the light more efficiently. What's interesting is that the opposite also appears to be true:

High light availability may also allow aquatic plants to lower the CO2 compensation point (Maberly 1983, Maberly 1985). This may be particular advantageous for mat-forming photoautotrophs in shallow water. In such systems, the light is often abundant whereas concentrations of CO2 inside the mat are low due to low intra-mat water exchange. Here, the interactions between light and CO2 may allow the photosynthesising organisms to extract CO2 more efficiently as a result of a lowered CO2 compensation point. 

I.e. higher light levels allow plants to better take advantage of existing co2. It may be that this is specific to certain species or it is possible that I'm misinterpreting this. If not though, this would seem to run counter to the prevailing EI orthodoxy. I.e. higher light is bad. On the basis of this Tropica article, higher light allows for more efficient use of co2 so higher light is good. Certainly it was the case in the Tropica experiment that plants in high light and low co2 grew faster than in low light and high co2. What's not reported is the health of the plants.


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## sciencefiction (29 Aug 2013)

> In a low tech tank it can be expected that c02 levels are low, in the same tank in the shade, both light and c02 will be low so growth will be much reduced which is likely what you are experiencing sciencefiction. Clive isnt wrong as more c02/ferts will yield better growth, but i suspect in your particular low tech tank that light may be the limiting factor.
> Cheerio,
> Ady.


 
Yes Ady, seems that no one is wrong. However, it seems poor growth is not just down to CO2 but light too in particular scenarios like mine when there's no CO2 supplement, and one can compensate light with co2 and vice versa to an extent to get healthy growth. That's how I read it and my tank is an example of what's happening to the shadow corner in my tank.



> We see that at low light and low CO2 Riccia fluitans is barely able to maintain a positive growth rate whereas at low CO2 and high light the growth rate is almost 6 fold higher. More importantly, at low light levels the addition of CO2 is able to stimulate the growth by a factor of almost 4!


 
And see their reasoning why providing CO2 is more desirable than light.....because they think one can still have inadequate light for particular species of plants in aquarium with the light we currently use if the tank is too deep. So adding CO2 instead is about compensating the plants for the lack of light down there. Hence why it's accepted that carpeting plants need lots of CO2 instead. But in my low tech the glosso is growing without CO2, so it must be getting adequate light to an extent. My tank is only 50cm so that's possible the reason it grows as I have high power LEDs over the tank. (forgot to say the glosso is carpeting and not leggy at all)



> It is often a much more difficult and expensive task to provide adequate light over the plant aquarium. Both fluorescent light and highpressure-quicksilver lamps may produce sufficient light if supplied with effective reflectors but in deep aquaria (more than 50 cm) is very difficult to offer enough light to small light demanding foreground plants. Based on our experiments, we suggest commencing CO2 addition before any other action is taken


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## Ady34 (29 Aug 2013)

It would be useful to know what "high lighting" levels are though. I suspect it is actually a lot lower than the kinds of light we choose to put over our tanks which is why we end up melting our plants even with co2 addition. Science fiction seems to have hit the right balance in that their plants are healthy and growing in the most part, if their tank were a high tech system with good flow/distribution of the co2 the difference between growth of the aponogeton a would be less obvious I suspect.
It seems plants can adapt strategy to light or co2 collection depending upon availability...they are not so good when both are limiting.


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## Ady34 (29 Aug 2013)

sciencefiction said:


> And see their reasoning why providing CO2 is more desirable than light.....because they think one can still have inadequate light for particular species of plants in aquarium with the light we currently use if the tank is too deep.  So adding CO2 instead is about compensating the plants for the lack of light down there. Hence why it's accepted that carpeting plants need lots of CO2 instead. But in my low tech the glosso is growing without CO2.


Well, not entirely as the article shows that co2 grows more plant mass, light dictates the speed at which they try to grow. Small foreground plants need more light to grow faster to fill in the space faster, we are impatient in the most part so it is desirable to have high light to speed up the process and get a 'carpet'.....however without matching the co2 to the light we end up in trouble. In your instance without co2 addition the plant will require less light to succeed but will grow at a much slower rate.
It is safer (plant health wise) to add more co2 and less light as that way you run into fewer issues either algae or melt.


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## sciencefiction (29 Aug 2013)

Yes, the rate of growth is affected but not the health of the plant unless one goes extreme I guess.  But at least now I understand why I have no problem with carpeting plants growing fine in a low tech enviroment without CO2. I might as well take a lot of pictures as the tank is coming down soon. But here is my glosso and bacopa australis carpeting in that same tank. Some of you may have seen it already. I don't have even one strand of glosso growing upwards, starving for CO2 as what's normally pointed out as a main reason. So regarding of theories, I either have very high CO2 in my tank or that article is right that light can compensate to an extent if fertilization is right. Yes, they are not growing very fast but they are growing.

That's after planting the glosso.






That's it today.


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## Ady34 (29 Aug 2013)

The article I'm sure is right, but we don't know the levels of lighting used. Light can compensate to a degree, but not entirely.
In your tank I'm sure the lighting and available co2 are well balanced which is why your experiencing good healthy growth, albeit a little slower  Maybe glosso is a species particularly good at converting water carbonates into useable carbon like vallis which is also doing well in your tank. There can be more variables and pieces to the puzzle which we may never know.
If you had longer time available you could increase lighting intensity and see what happened, I would suspect structural failure as the plant could not feed itself fast enough without co2 and fertiliser addition. You could also swap the two aponogetons positions and see what happened to them without altering any other variables (like I say it may well be light in this instance which has created the difference)...but as you say you have to take the tank down, and I'm sure even if you didnt have to you wouldn't want to potentially ruin the balance as its going so well. I'm sorry to hear about the leak, hope you get it resolved as the tank is doing really nicely now, 'from the Disaster to Success' may be a better title for it now 
Cheerio,
Ady.


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## sciencefiction (29 Aug 2013)

That's what it says about the light and CO2 levels in the article without specifying much:



> High light corresponds to light levels found in nature near the water surface or in an extremely well illuminated aquaria with high-pressure mercury lamps or halogen lamps. In fact, the medium light intensity in this study corresponds to a standard well illuminated plant aquarium. Low CO2 corresponds to the CO2 concentration found in many lakes or in an aquarium without CO2 fertilisation - but with an aerating pump running. High CO2 is 40 mg/l, which can be found in many small groundwater feed streams and it is also the maximum level recommended by most experienced plant aquarium keepers.


 


> At very low light intensities, the incident light is insufficient to sustain a positive photosynthesis and the net oxygen budget of the plant is negative. In other words, the respiration processes exceed the photosynthesis. At a certain light level, however, the two processes equal each other and we have then defined the light compensation point of the plant. By illuminating the plant with still higher light intensities the photosynthesis is also positively stimulated in linear way. *At high light, the resulting outcome from the photosynthesis becomes less until it finally levels out at a point where we have the maximum photosynthesis. From this point on, more light will not translate into a greater photosynthesis.*QUOTE]


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## sciencefiction (29 Aug 2013)

> Maybe glosso is a species particularly good at converting water carbonates into useable carbon like vallis which is also doing well in your tank.


I didn't even know glosso can do that. I know about valis, hence it grows better in harder water and almost anyone can grow vallis. But in my case it took quite a while for it to take off and it wasn't the first plant to recover so I don't think it's indication of anything but who knows.

Vallis on the 30th June 2.5 months after planting(a few strands visible halfway the height of the tank out the back.






Vallis on the 4th August finally taking off, but the same did the rest of the plants.







> You could also swap the two aponogetons positions and see what happened to them without altering any other variables (like I say it may well be light in this instance which has created the difference)


 
I could just remove the emersed plant pots and the light will be unblocked again to that aponogeton and the surrounding plants. I just can't do that right now but I would have and even before posting today here I've been thinking for a few weeks where to move the emersed plants without compromising other plants like that. If it comes to taking the tank apart completely, I'll switch the aponogetons around or just plant both in the middle back somewhere and keep the corner to anubias and crypts only and hopefully vallis or whatever else I can find that can deal with that shadow.


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## Tim Harrison (30 Aug 2013)

I read this article well over a year ago and it's apparently become something of a Bible...in that it seems to be grossly misunderstood or open to interpretation depending on your religion...or rather preconceived ideas and/or dogmatic devotion to certain paradigms. For instance, take the opening quote...

*'Poor growth in plant aquaria has usually been attributed to insufficient light over the tank and when asking the experts, the advice has always been to increase the light availability before any other action is taken. New research shows that this may be poor advice, in particular, for an aquarium without CO2 fertilisation'*

This is very true and I'm not going to argue against this at all...however the key phrase is "the advice has always been to increase the light availability *before* any other action is taken"...this does not mean that in - some, a lot, or even most cases light and not CO2 is the main limiting factor to growth...it just means that we should ensure other variables - CO2, fertz, and flow and distribution - are sufficient first.

I can't be bothered to read the article again but from what I remember the results of the research actually indicated that *high* light and* low* CO2 provide better growing conditions than *high* CO2 and* low* light, but together high light and high CO2 can provide optimum growth rates (whatever the authors definition of high and low light/CO2 are, but I imagine you don't have to look any further than their plant catalogue to find out). In fact, the overall assumption of the paper is that light is indeed often the limiting factor to growth, but it nevertheless advocates the use of CO2 to further increase plant growth.

So in conclusion perhaps blaming all our tank woes on low CO2 is not always right or particularly helpful...it could actually be that in many cases the "experts" are right to advise increasing light availability...but just as long as all the other parameters are adequate too...certainly my own experience corroborates this.

Just one more point on plant LCP - yes you can grow plants at PAR levels just above it but they ain't gona be very happy nor are they gona float anyone's boat aesthetically...


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## Ady34 (30 Aug 2013)

Troi, the article shows that high co2 and low light yields much greater plant mass gain than high light and low co2. Low co2 is a greater inhibitor than low light hence the advice to keep light low and try to optimise co2, especially given how notoriously tricky it is to keep the darn gas in the tank and put it where we need it.   Co2 is the daddy, especially in our high tech tanks. Good proportions of co2, ferts and light are the most productive scenario, but that's harder to hit the sweet spot.....infact I've never hit it yet 
Cheerio
Ady


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## sciencefiction (30 Aug 2013)

Ady34 said:


> Troi, the article shows that high co2 and low light yields much greater plant mass gain than high light and low co2. Low co2 is a greater inhibitor than low light hence the advice to keep light low and try to optimise co2, especially given how notoriously tricky it is to keep the darn gas in the tank and put it where we need it. Co2 is the daddy, especially in our high tech tanks. Good proportions of co2, ferts and light are the most productive scenario, but that's harder to hit the sweet spot.....infact I've never hit it yet
> Cheerio
> Ady


 
I think Troi is right. See figure 3 to the right side of the article and here is the explanation from it:



> The figure shows how 1 gram of Riccia develops over two weeks under the given light and CO2 levels. At low light and low CO2, Riccia is barely able to maintain the biomass and 1 gram turns into 1.16 gram after two weeks (the white line). *At low light and high CO2, 1 gram turns into 1.75 (the green line) and at high light but low CO2, 1 gram turns into 2.41 gram.* The combination, however, paramounts the effect from the individual resources and at high light and high CO2, 1 gram turns into 6.90 gram.


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## Ady34 (30 Aug 2013)

I stand corrected, the article does indicate a greater plant mass increase due to light over co2. A marked increase is then noted from the addition of both high light and high co2.
I think I'll have a proper read of the article again!
Its too late now though


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## Tim Harrison (30 Aug 2013)

It's not particularly well written in places and can be a bit confusing ...I guess something has been lost in translation to English ...


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## dw1305 (30 Aug 2013)

Hi all,
As some will know I'm not an "added CO2" user, but I think an important factor in all of this is that elevated CO2 levels will actually reduce the LCP.  Sorry it is a bit of strange link, but it is quite useful: <Teachers' Guide - Plants And Light - Tomatosphere>.

It was because of the CO2 factor that I used a floater for the "Duckweed Index". Because the leaves have access to atmospheric CO2 (at 400ppm) it removes CO2 from the equation. This allows us to just look at the relationship between PAR, nutrients and growth.  

I've some-how managed to post the same link twice in my previous post, but the other old thread I meant to link to was this one (from 2010): <Light Compensation Point and optimal PAR levels | UK Aquatic Plant Society>, and particularly this post. 





dw1305 said:


> I recently bought a new light (2nd hand via UKAPS) which doubled the light output and one very noticeable effect has been I have a lot more biomass in the aquarium, in this case light availability was limiting plant growth (although I practice nutrient depletion and would have said that plant growth was nutrient limited before the addition of the light).
> 
> I can't measure the PAR at the bottom of the tank, but I'd be reasonably confident that I'm now maintaining light levels at the tank bottom (by an occasional thin through of the floating plants and upper canopy stems/leaves) at pretty much the same level as it was before the new light, the only difference is that there is now more energy in the system and this has allowed a thicker canopy to grow.


cheers Darrel


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## Graham1984 (30 Aug 2013)

So, it theory, If i went with a 2lt diy co2 set up with my low light, but circulated the water a bit more, my results will be better, Not show stopping but better.
I know I cant provide anything near enough co2 to grow thick low growing carpets, but at the same time thats not what wanting to do anyway.

for me the idea behind the low tech approach was to maybe to try to avoid getting bogged down in the science bit. Ive been down the high tech/energy path before
and found it to involved for the time/money I have available to me. (im sure others are in the same boat.)

with the t8s, I have 0.9wpg, and with t5sho, I have 1.6wpg and the higher intensity, I know PAR is the better way to asses light these days, but I dont have the equipment to do that.

from what I understand, water from the tap will contain co2, my soil sub will produce some co2, and if I have a diy set up that is well circulated with causing too much surface movement,  In "old money" both levels are fairly low, so I should get some sort of growth out of what I have, I dont mind doing a bit more water work to keep things looking good, if providing some co2 and a bit more light will give me better results. (all be it not at the optimal levels)


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## Ady34 (30 Aug 2013)

Troi said:


> It's not particularly well written in places and can be a bit confusing ...I guess something has been lost in translation to English ...


To be honest I think I completely misread it 
The article seems to contradict somewhat the current train of thought regards light and co2, however I'm guessing tests on individual species would be more telling and perhaps more complete an assessment. I will re read it but perhaps more information on the tests would be helpful. Riccia is a floater by nature so perhaps that has something do do with it? Perhaps a new topic of discussion based on that article would be good.


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## Tim Harrison (30 Aug 2013)

dw1305 said:


> Hi all,
> elevated CO2 levels will actually reduce the LCP.


 
And vise-versa...elevated light levels will reduce the CO2 compensation point... from the same paper - 'With more light available, less investment in the light utilisation system is necessary and the free energy can be invested into a more efficient CO2 uptake system so that the CO2, which is present in the water, can be more efficiently extracted.'

At the end of the day all we are trying to do is reduce our plants need to adapt to resource limitation. Adaptation to resource limitation can be very expensive reducing the energy available for growth.


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## Tim Harrison (30 Aug 2013)

Ady34 said:


> To be honest I think I completely misread it
> The article seems to contradict somewhat the current train of thought regards light and co2, however I'm guessing tests on individual species would be more telling and perhaps more complete an assessment. I will re read it but perhaps more information on the tests would be helpful. Riccia is a floater by nature so perhaps that has something do do with it? Perhaps a new topic of discussion based on that article would be good.


 
Maybe the current train of thought is wrong...or alternatively - like a lot of planted tank paradigms - it's just been misinterpreted and/or misunderstood. I think that forums like ours sometimes get caught in a bit of a bubble and we tend to create our own paradigms that become entrenched beliefs even though they were originally based on nothing more than aquarium folklore. The problem then is that it's often difficult to accept an alternative, or more accurate, hypothesis even though supporting scientific evidence is staring us in the face; it's often considered heresy. It's nothing new the Catholic Church have been resisting paradigm shifts that question their dogma for centuries...hence the various inquisitions...DAHHH...NO ONE EXPECTS THE SPANISH INQUISITION!!!...


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## dw1305 (30 Aug 2013)

Hi all,


Graham1984 said:


> for me the idea behind the low tech approach was to maybe to try to avoid getting bogged down in the science bit. Ive been down the high tech/energy path before


I think your right, personally I stick any available light over the tanks (most of my tanks and lights are "pre-owned" or DIY), use whatever substrate I have to hand, plant heavily, maintain a large plant mass and then feed (if necessary) via the "Duckweed Index" <Low maintainence, long term sustrate | UK Aquatic Plant Society>. It is a KISS solution.

If I wanted to go even lower maintenance I'd go for a wide shallow tank with a large surface area to volume ratio, the advantage of this is that a larger gas exchange surface means quicker diffusion of CO2 and oxygen both in and out. I think tank architecture is part of the reason why "BigTom's" "Bucket of Mud" has been so successful, and if you read through his journal  <Tom's Bucket O' Mud - new vid page 28 | UK Aquatic Plant Society> you can see it is an absolute triumph.


Troi said:


> At the end of the day all we are trying to do is reduce our plants need to adapt to resource limitation. Adaptation to resource limitation can be very expensive reducing the energy available for growth.


This is true, but I think resource limitation can be a useful tool. I'm not aiming for optimal plant growth, quite the opposite, I'm aiming for a low level of sustainable growth. This might seem a strange aim, but there is a reason for it.

*I want plant growth to be limited by the availability of nutrients*, my principle aim is to have the plants mop up as much of the available nitrogen as possible. Plant - microbe biological filtration is extremely efficient, which allows it to deal with large bio-loads in sewage treatment systems etc., but it also means that you can use them to maintain very high water quality. 

cheers Darrel


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## Ady34 (30 Aug 2013)

There's always more to anything that meets the eye, but I'm for sure not going back to more light is best! The problem is all things are relative and whilst light can yield better results in that particular test, in our home tanks many fail due to over lighting and under feeding, hence why co2 is such a hot topic. People have felt the need to use very high lighting in an attempt to succeed and have ended in failure due to not paying attention to other important factors like co2 and distribution which is proved along with light to yield the best overall results. The ideal scenario is to have unlimited everything  limiting light is safest due to the implications of over lighting. matching co2 and lighting is much better than limiting one or the other, more often than not it is the co2 that is limiting and not the light as that's easy to plug in over the tank. Co2 is much more tricky to get right. I think what is clear is that if you want to grow fast then co2 is as important as the light.



Graham1984 said:


> So, it theory, If i went with a 2lt diy co2 set up with my low light, but circulated the water a bit more, my results will be better, Not show stopping but better.
> I know I cant provide anything near enough co2 to grow thick low growing carpets, but at the same time thats not what wanting to do anyway.
> 
> for me the idea behind the low tech approach was to maybe to try to avoid getting bogged down in the science bit. Ive been down the high tech/energy path before
> ...


Hi,
If your trying to avoid being bogged down in the science I'd say stick to the t8 lighting and go low tech. Don't even think about co2. If you have good success with the t8s and want to try for more growth add higher light and see what happens, if the plants react badly then you'll know you need to either reduce light intensity again or provide additional food.
Cheerio
Ady


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## dw1305 (30 Aug 2013)

Hi all,


Graham1984 said:


> water from the tap will contain co2, my soil sub will produce some co2, and if I have a diy set up that is well circulated with causing too much surface movement, In "old money" both levels are fairly low, so I should get some sort of growth out of what I have, I dont mind doing a bit more water work to keep things looking good, if providing some co2 and a bit more light will give me better results.


Should also have covered this. You can ignore the CO2 from the tap, it will equilibriate with atmospheric CO2 levels pretty quickly once the water isn't under pressure. The production of CO2 from the substrate and bio-load respiration may be quite high, but levels will build up mainly at night and this means that you run the risk of asphyxiating your fish before the lights come on.


Graham1984 said:


> So, it theory, If i went with a 2lt diy co2 set up with my low light, but circulated the water a bit more, my results will be better, Not show stopping but better. I know I cant provide anything near enough co2 to grow thick low growing carpets, but at the same time thats not what wanting to do anyway.


More flow is very relevant, mainly because it increases the gas exchange surface, if you are adding CO2, it means it will be lost more quickly, but if you aren't adding CO2, as the gas exchange surface becomes larger the levels of CO2 in the water and atmosphere will reach equilibrium more quickly. In most situations this is a "win win" situation as both dissolved oxygen and CO2 are constantly replenished.

cheers Darrel


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## roadmaster (30 Aug 2013)

Ady34 said:


> Well, not entirely as the article shows that co2 grows more plant mass, light dictates the speed at which they try to grow. Small foreground plants need more light to grow faster to fill in the space faster, we are impatient in the most part so it is desirable to have high light to speed up the process and get a 'carpet'.....however without matching the co2 to the light we end up in trouble. In your instance without co2 addition the plant will require less light to succeed but will grow at a much slower rate.
> It is safer (plant health wise) to add more co2 and less light as that way you run into fewer issues either algae or melt.


 

I think folk's are impatient period..


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## Tim Harrison (30 Aug 2013)

Ady34 said:


> There's always more to anything that meets the eye, but I'm for sure not going back to more light is best! The problem is all things are relative and whilst light can yield better results in that particular test, in our home tanks many fail due to over lighting and under feeding, hence why co2 is such a hot topic. People have felt the need to use very high lighting in an attempt to succeed and have ended in failure due to not paying attention to other important factors like co2 and distribution which is proved along with light to yield the best overall results. The ideal scenario is to have unlimited everything  limiting light is safest due to the implications of over lighting. matching co2 and lighting is much better than limiting one or the other, more often than not it is the co2 that is limiting and not the light as that's easy to plug in over the tank. Co2 is much more tricky to get right. I think what is clear is that if you want to grow fast then co2 is as important as the light.


 
I'm sure you're right, and the main gist of the Tropica paper supports your view...really all it's saying is what we already know - light is of key importance to plant growth and health but you can have too much of a good thing...

I think that perhaps where we maybe going wrong is to assume that CO2 is a panacea at the expense of providing adequate lighting...all parameters have role to play - especially light - and we need to balance them according to our goals, whether it's a supercharged injected tank or whether you want plant growth to be limited by nutrient availability like Darrel.


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## roadmaster (30 Aug 2013)

I was called away from my computer before I could finfish my thought's.
I think if low tech,or low energy,low maint,is ones goal then they should choose that method and someones advice and follow it.
I chose Tom Barr's NON CO2 method and have no complaint's.
I also enjoyed Troi's tutorial on soil based tank's, particularly the CO2 he mentioned that can be generated from the soil.(So I added soil base).
This along with CO2 as by-product of fish respiration,is what it is in my tank's.I add dry fertizer's as per Tom's method and that leaves only the lighting to worry bout or adjust. Ten hour's of my present lighting bring's hair algae, Seven hour's is all I can use at present.
Plant's grow slowly and it took two year's for growth seen in my avatar.
Hardest part for me,,was waiting for the puny sprig's I purchased to fill out in 300 litre tank but it gave me more time to study/learn from folk's here.
 I think many folk's grow tired of the waiting,but now,,when I need to place plant's in another tank or move plant's about to create new look,,I have mature specimen's to quickly fill in where i need them.No waiting for mature plant's to reach good size,,no melting from transistion from emmersed to submerged..and no constant battles with algae from desire to flood the tank with more light than the low energy method can tolerate.
I very much like the discussion's in these type thread's and have learned a great deal.
Am never as amazed by that which I don't know,,as I am by that which I thought I did know.


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## Ady34 (30 Aug 2013)

Agreed Troi.
Trouble is always that both co2 and light are lowest at the substrate level. To get higher levels of light down there then the upper regions will automatically be exposed to 'megawatt' proportions of par. In that respect increasing distribution of co2 to get it down there may be better for the overall health of the tank being as co2 can reduce lcp? Just a thought....


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## Tim Harrison (30 Aug 2013)

And it's a thought that makes perfect sense...and is in total accordance with my previous comment...it's still all just about balancing the right light levels with other parameters - CO2 or otherwise.


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## bridgey_c (30 Aug 2013)

Im new to this game with about one years experience of co2 injection. I might be wrong then but thinking more about Troi's points, I think it was such a hurdle in the past to convince people that more light, 99% of the time is not better, that it took a sledgehammer to smash the nut, so to speak. When the beginner walks into a fish store and walks out with a tank with T5 lighting they will not have too little light. I guess then that in 99% of the problems, too little light is not the answer. Getting people away from thinking they need more light was such a tough sell in the past that the mere thought of it ever being advised again probably sends shivers down the backs of the 'heretics' who first proclaimed it.


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