I tested the LED strips. I did use it in a large aquarium, and they do work. Unlike the neon tubing, they do not heat, cause no IEM interferences (i had electronic parts along the tubes that didn't funtion properly), and should not require to be changed often. Furthermore, i could remove the neon ballasts, removing quite some weight from the system.
As of now, the LED are powered by an ATX PSU, that i'll end up using to also power TEC units to chill the water.
The plants seems happy with it, and the animals in the tank seem unaffected.
However, the light is kind of bluish, and feels dim to the eye. There may be a difference of perception due to the color change, but i'd like it to be brighter. Without a mean to measure actual light output, i'll just rely on my feelings. So i ordered other LED strips : this one from fastech that provides 9000 Lumens in warm white (i also ordered the cold white version, ideally i would have liked the pure white version, but i'll combine both and see how it works), and this strip, that provides 12 000 lumens of cold white (yes, it's over nine thousaaands!).
All in all, yet more cheap led strips from china (but fasttech is less slow/faster than aliexpress). I'll test it out when it arives, but for now i'll just add more led strips to compensate...
In this case, the strips are placed on L-shaped aluminium bars, used to provide both support and cooling. In practice, those LED produced little to no heat, so i could have stuck it on plastic for same results.
So all in all, i'm happy with the principle, but i want to improve either with better LED, or more low quality LED.
I measured the power usage of the system, and with the 3 neon tubes, i did use 130W of power, while now i'm using around 50-60W, including the PSU (power measured at the plug so that's including the pumps).
Since it so much thinner and lighter, i'll be able to get rid of my big white wooden conainer box, and replace it witha lighter structure, held in place with transparant wires.