LED Color Distribution for Planted Tanks

  • #1
Hey everyone,

Quick question on LED color distribution for planted tank lighting.

I've seen each of the following statements made online, many of which contradict one another:

  • Red lights should take up at least 50% of your LED spectrum, while blue lights should not exceed 15% (with the rest, of course, being white).
  • You don't want to overdo it with red lights, since having them on for a prolonged period of time will result in excessive algae growth.
  • Red lights are useful to the plants that they reach in shallow tanks; however, as blue light permeates further, blue lights should be optimized when lighting a deeper tank.
  • Shoot for 75% of your spectrum being composed by blue lights, 20% by white lights, and just 5% by red lights.
  • It doesn't really matter, as long as you don't overdo it with the blue lights.
Despite the internet being information-rich for most niches of the aquarium hobby's world, there seems to be limited discussion on this and even less consensus.

Does anyone have input on the matter?

Thank you!
  • #2
I have a Fluval Plant 3. I set the 3 white lights up to 100% and the blue and red at 0. I have crypts, vals, frogbit and anubius nana doing well with Thrive liquid once q week and root tabs every 3-4 months.

I've read blue is used mostly by algae.
  • #3
I've heard the same as kansas - that excessive blue light can cause algae issues. But honestly, I have no idea. I use whatever's called "full-spec" without many issues. A lot of my tanks have algae but that's because I'm a lazy dude and I don't like doing a lot of maintenance. Algae's also good for the environment in small quantities - my thoughts: "if algae's good and I don't feel like cleaning it, then any light works."

Here's some input on lighting for all of my tanks:
•10G temporary goldfish - aqueon FW light - has mostly white and some blue. I have several spp. of anubias, java fern, crypts, b. caroliniana and a few riparium plants - sweet potato, pothos, split-leaf philodendron and arrowhead. This tank has green spot but I leave it on the sides & back, sort of like a natural background. It had BBA but only when decreasing flow. Once fixed it's never had issues!
•2G shark-shaped windowsill tank - busy natural sunlight. It has brown diatoms but it's not bad. It only harbors spider plants, no aquatic plants.
•5.5G rescue betta tank - also has brown diatom but it's hardly an issue. Simply wipe it off and it's not an issue any longer. This was a free 'kit' so it only has white LEDs. Egeria, java fern & anubias are growing slowly but doing fine overall.
•(2) 2.5, moss bowl, 5.5 & .5G windowsill tanks - sunlight only. The 2.5's are faux blackwater and have egeria/pothos only. Many microorganisms, algae's virtually non-existent except for a tiny bit of green spot. The 5.5G ecosphere has a rescue paradise fish (I've raised him for over a year but he doesn't grow, possibly due to the camallanus he had when I rescued him). This has english ivy, pothos, arrowhead, purple waffle, egeria, mondo grass and salvinia. Throughout the years it's had many species of microorganisms and algae but it finally settled with only a tad bit of green slime algae. One bowl is a paludarium with wild moss spp. and liverwort. The other 1G bowl's similar, neither have algae even with bright sunlight!
•2.5G betta & 5 black kuhli loaches (temporary) - no lighting yet but I plan on adding a desk lamp. No algae at all, not even with the temporary high stock and melting leaves. Has 2 spp. of anubias, a huge "carpet" of java moss, maybe corkscrew val, a small sword, a crypt, L. nummularia and a few palm-like riparium plants (not sure what).
•3G cube for Val the betta Gal. It uses a long LED strip light from target. This has java moss, some spp. of anubias & java fern, salvinia and massive arrowhead plants. Due to it being tinted, it never had algae issues, even with high lighting. Sadly, I cross-contaminated with another tank and it has green spot, used to have BBA (I don't think it has it anymore) and maybe green hair algae. If I had separate supplies, this tank wouldn't have algae.
•5.5G with a rescue betta, nerite snail and I think ramshorns unless they died off. This tank is very deeply tinted and only has 1 large A. congensis. Riparium plants include pothos, english ivy, sort of struggling lemon button fern & parlour palm. This tank has absolutely no algae whatsoever. I don't even think it could harbor any! This also is a "kit" with only a few small white LEDs.
•2G temporary with a rescue betta, C. habrosus and a HUGE ramshorn! This has thriving salvinia and a tiny patch of süßwassertang. Green spot took over for awhile but it's clear now! This is a very old "kit" and has full-spec lighting. I used it to propagate egeria and swords at one point! It always seems to attract green spot though :/
•Last but not least, another 3G cube for a rescue family betta. Has a tiny full-spec LED strip gifted to me, massive anubias, L. nummularia, random buces, pennywort, windelov java fern, split leaf philodendron & pothos. The anubias came from a different tank with fuzzy algae. It's grown a bit but I think it's dying (dirted, a bit of sunlight and same lighting as where it came from).

Anyhow, I hope my extraordinarily long reply can help, whatever you can get out of it. Good luck! ;)
  • #4
I had some serious algae to start. More plants helped outcompete the algae and amono shrimp eat it, so it's pretty much under control even with 12 hours of light every day.
  • #5
In my experience, getting the perfect color ratio isn't that important for growing plants. The colored lights we use are more important to how the plants look to us. I'm willing to splurge on high end lights, because I like my tanks to look nice. But, I've grown plants with mostly red lights, mostly blue lights, white lights, and full spectrum lights. The plants I've grown seem to be able to adjust to just about anything.

At the moment, I'm growing my plants with a near even spread of red, green, and blue LEDs (and no white LEDs). And, the only reason I've chosen these ratios is because I think it looks nice. Plants are happy.

I think PAR is much more important than any specific color ratio.

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