Low tech lighting levels

[Graham1984]

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,

 

[ceg4048]

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,

 

[Graham1984]

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.

 

[Michael W]

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.

 

[Graham1984]

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?

 

[foxfish]

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

 

[Graham1984]

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.

 

[Graham1984]

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?

 

[Michael W]

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.

 

[Aseph]

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.

 

[ceg4048]

Is under lighting a tank not a risk?

No.

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,

 

[dw1305]

Hi all,

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

 

[sciencefiction]

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

 

[ceg4048]

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,

 

[Aseph]

No.



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,

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

 

[sciencefiction]

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.

 

[ceg4048]

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.

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,

 

[sciencefiction]

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.

 

[Tim Harrison]

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?

 

[hotweldfire]

No.



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,

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