LED Lighting

The science behind successful fishkeeping.
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jacksdad
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Further to previous discussions, I thought I'd start a new post about LED lighting :D
My tanks both have lamps from the same Chinese maker, Seabillion. The lamps have 2 rows of white leds and a centre row of red, green and blue. RGB leds.
I've worked on the circuit boards so the rows of white and rgb leds can be lit independently and are controlled by a TC420 unit, also from China. The TC420 has 5 channels which can be programmed on a laptop to come on at any time, and at any %age of supplied power. Mine are 12V, the longest has 99 leds, 33 white x2 and RGB x1, each controlled alone. The other has 63 leds , white 21 x2 on one channel and RGB x21 the last (TC420 only has 5 outputs).
So! Now I have both tanks running on the controller (timer), starting in the morning at just 10% then rising to 'midday' at 90 & 100% followed by a fade to dusk & off at about 11pm.
The long lamp is described as "Full Spectrum" 50W and 5500lm Lumens. The other is full spectrum and 32W 3500 lm.
I'm trying to learn about the physics/chemistry of the lighting, to better understand how to look after my tanks.
The 160 tank is doing very well, the plants are growing so well I have to cut them back every week, but the 260 tank is struggling: All my red leaf plants have died, but the Elodea densa is doing very well, in contrast to all the other plants.
What are the pros and cons of pure white lighting, or white and blue, and then RGB?
My RGB leds make a large range of colour bands:

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Do the plants (and fish, snails, shrimps) benefit from all these different colours? I assume its replicating natural sunlight, as this splits up into colours if you use a prism, like we did way back in physics lessons! :D
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lunar jetman
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jacksdad wrote: Fri Nov 15, 2019 14:26 pm Do the plants (and fish, snails, shrimps) benefit from all these different colours? I assume its replicating natural sunlight, as this splits up into colours if you use a prism, like we did way back in physics lessons! :D
I'm just between meetings at work at the moment so haven't got time to find the details I had somewhere on lighting which I think will be of use, but in short, yes plants benefit from the full light spectrum and would suffer with just a white light.
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mikeyw64
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sounds very much like the one I've got (except I havent done any mods so its on/off white+RGB / RGB only)

https://www.ebay.co.uk/itm/Aquarium-Fis ... 4118846723
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fr499y
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lunar jetman wrote: Fri Nov 15, 2019 14:59 pm
jacksdad wrote: Fri Nov 15, 2019 14:26 pm Do the plants (and fish, snails, shrimps) benefit from all these different colours? I assume its replicating natural sunlight, as this splits up into colours if you use a prism, like we did way back in physics lessons! :D
I'm just between meetings at work at the moment so haven't got time to find the details I had somewhere on lighting which I think will be of use, but in short, yes plants benefit from the full light spectrum and would suffer with just a white light.
They wouldn't suffer, and don't.

6500k white ( classed as day white ) contains plenty of red and blue spectrum that plants need and use. The higher the kelvin, the less red you get and more blue. IF you was running a 14000k white on its own then yes you would struggle, but a 6500k or 8000k contains enough reds and blue for the plants to use. Here's a small graph so you can see what i mean.
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And here's my light with 6500k white and blue LED only ( No struggle on growth at all )
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The old days of planted aquariums ( Dutch scapes for one ) used T8/T5 and MH lighting, with mainly white tubes. No issues with growing plants. Its more to do with the colour WE see rather than benefits to the plants/fish.

I use a red/white/blue unit that i made up, but it's only for a sunrise/sunset effect more than anything :)

Some examples

6500k white
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2x 3000k, 2x 6500k
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3000k and 6500k
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lunar jetman
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fr499y wrote: Fri Nov 15, 2019 15:25 pm
lunar jetman wrote: Fri Nov 15, 2019 14:59 pm
jacksdad wrote: Fri Nov 15, 2019 14:26 pm Do the plants (and fish, snails, shrimps) benefit from all these different colours? I assume its replicating natural sunlight, as this splits up into colours if you use a prism, like we did way back in physics lessons! :D
I'm just between meetings at work at the moment so haven't got time to find the details I had somewhere on lighting which I think will be of use, but in short, yes plants benefit from the full light spectrum and would suffer with just a white light.
They wouldn't suffer, and don't.
Apologies, that'll teach me to read properly and try to rush a response!

The lighting spectrum is of course key and plants only need the red and blue parts of it.

Here's one of the articles from the Tropica site I was looking for.

https://tropica.com/en/guide/make-your- ... ess/light/
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fr499y
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Don't get me wrong, units with red and blue are great for tweaking and making plants look 'better' to the eye.
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