Below 420nm is it necessary?

[Heabel7]

In my search for new lights I have found that many of the budget led fixtures lowest led is 420nm. From many, many post I have seen multiple success stories from likes of reefBreeders and black boxes that not only provide a good looking tank but get results. In addition, ATI blue plus seems to cut off mostly at the 420Nm mark as well as their atinic bulb peaking at 420nm. However, most of the expensive brands LED have multiple diodes below 420nm. In addition, one of the post from Danna Riddle shows that sps corals do use a fair amount of light below 420 even into the black zone.

Is LED below 420 necessary? And if so what should I expect the benefits to be? If not why?

 

[Little_Red_Ryan_Hood]

I am not a lightning expert by any means, so take my opinion for what it is worth. There is evidence that the lower nm ranges have an effect on photosynthesis.

My experience with black boxes that don't have 380 nm bulbs has been ok, but the corals would likely do better with it. My point is that you don't need it to grow corals. If you want cheaper black box set up, you could always add a couple T5 actinic bulbs to eliminate that concern.
Most people like the extra pop that comes from actinic lighting especially if they are selling coral.

ATI blue plus bulbs have a peak at 460, but they do have some amount of lower nm light. Florescent bulbs have a much wider range of color per bulb than led's. Higher end fixtures usually take that into consideration and add a more diverse array of bulbs.

I have run black boxes for years on a SPS dominant system and the have grown coral just fine. Although, I would argue that higher end lighting systems would produce better results. There is nothing wrong with cheaper options. Just keep your expectations in check. Budget friendly options will work.

Hope that helps you.

 

[Little_Red_Ryan_Hood]

In addition, UV LED bulbs are only effective for about a year. Then they stop working properly and need to be replaced.

 

[Ron Reefman]

I'm not an expert when it comes to led fixtures or the spectrum that corals REALLY need.

However, I've been running led fixtures since the day they added dimmers (a long time ago). And I'll let the look of my tank speak for itself (photo at the end).

I don't think anything below 420nm really does much, if any good. It may make colors pop a tiny bit more. I have a 380nm flashlight and when I shine it in my tank with just blue and violet leds on, I don't see any difference.

As far as photosynthesis goes, I haven't read any science that says corals need or even use spectrum below 420nm to do photosynthesis.

My 40g cube:

 

[jda]

Dana Riddle did a lot of work on proteins with excitation and emission and nearly all can use energy down to about 360-380nm. All of them use can use a wide range. Do all coral really need it? Who knows, but probably not. Do some coral do well with it? Nearly certainly. Remember that lower nm waves have more energy.

Some of this gets down to what you believe for science. If you are one that believes that organisms have adapted to use every available ounce of "everything" that they have available to them (except for Pandas), then you will probably want to include some spectrum from 350-850nm since there is real science that nearly all organisms can use all spectrum in this range... and nature would indicate that they have developed not to waste any of it. However, it does not appear necessary that have this full range for all corals, even if it would be more ideal. Some specialty corals probably need a wider range.

The last reason to use some UV is that some corals, but not all, will produce sunscreen pigments to protect or reflect those wavelength - you will not get these if you do not have the wavelengths.

IMO, the only reason that most LEDs do not have true UV is that the diodes are expensive and do not last long, thus negating the best selling points. Once cheaper and longer lasting diodes become available, you can bet that every manufacturer will add them with "best light ever" attached to the advertising.

I would not chase this, but there is a real reason that people see differences when adding T5s to their LEDs - one of these is the lower nm spectrum when using bluer bulbs. If you can do this, then cool, if not, then just be happy with what you have and if you choose to keep some tricker corals that seem more colorful under other types of lights, then worry about it then. You might not ever know the difference, depending on what you are going to keep.

 

[oreo54]

No doubt plenty of photosynthesis occurs below 420.. but it can be considered "optional"..

 

[Bpb]

Sub 420 is absolutely not necessary. I’ve seen some absolutely massive acropora colonies grown using royal blue and cool white alone. If it can be done, that automatically proves it not NECESSARY. Do shorter wavelengths of visible light and UVA lead to more interesting color development? Seems to be the case. I’ll throw my hat into the “optional but not necessary” category. The most dramatic color I seem to see hold stable in captive sps seem to be in lighting solutions that have some sub 450nm light present

 

[jda]

Again, I would only chase this if you have the kind of personality who wants the very best and can really tell. Also, you kinda need to keep the stuff where it can make a difference - like some of the trickier acropora, some speciality anemones and some clams. There absolutely is a difference, but most people cannot even tell nor keep stuff where it really matters. For the stuff that matters, it is kinda like eating only McDonalds where having a balanced diet is not "necessary" but you can tell a difference if you mix in some fiber, fruits and veggies.

Check out all of the posts where people add T5s to their tanks - this is one reason why they like them. You don't find too many who regret this decision. Even a Blue Plus from ATI has some and True Actinic has even more.

 

[oreo54]

ATI ACTINIC

Light in the Reef Aquaria

Light is one of the main life-supporting resources on our planet. Being photosynthetic, many marine invertebrates require light to live; Their symbiotic zooxanthellae need light for photosynthesis to produce sufficient nourishment both for their own use and for the host coral.

reefs.com

 

[robbyg]

Corals can adapt to a certain degree so going below 420 is more of a choice than a necessity. I would once again beg people to consider your own eyes and the effect this kind of light has on them before using it.

 

[Heabel7]

I'm not an expert when it comes to led fixtures or the spectrum that corals REALLY need.

However, I've been running led fixtures since the day they added dimmers (a long time ago). And I'll let the look of my tank speak for itself (photo at the end).

I don't think anything below 420nm really does much, if any good. It may make colors pop a tiny bit more. I have a 380nm flashlight and when I shine it in my tank with just blue and violet leds on, I don't see any difference.

As far as photosynthesis goes, I haven't read any science that says corals need or even use spectrum below 420nm to do photosynthesis.

My 40g cube:

Great looking tank

 

[Heabel7]

Again, I would only chase this if you have the kind of personality who wants the very best and can really tell. Also, you kinda need to keep the stuff where it can make a difference - like some of the trickier acropora, some speciality anemones and some clams. There absolutely is a difference, but most people cannot even tell nor keep stuff where it really matters. For the stuff that matters, it is kinda like eating only McDonalds where having a balanced diet is not "necessary" but you can tell a difference if you mix in some fiber, fruits and veggies.

Check out all of the posts where people add T5s to their tanks - this is one reason why they like them. You don't find too many who regret this decision. Even a Blue Plus from ATI has some and True Actinic has even more.

I did notice my colors come around when I added T5 supplements (2 blue plus bulbs). Hmmmm. Think it accelerates growth as well?

 

[Bpb]

Corals can adapt to a certain degree so going below 420 is more of a choice than a necessity. I would once again beg people to consider your own eyes and the effect this kind of light has on them before using it.

Do you have any scholarly/peer reviewers sources to indicate similarities in effects of near UV and UVA light on photosynthetic Cnidaria and the lens and cornea tissues of the human eye?

 

[robbyg]

Do you have any scholarly/peer reviewers sources to indicate similarities in effects of near UV and UVA light on photosynthetic Cnidaria and the lens and cornea tissues of the human eye?

https://www.aoa.org/Documents/OptometryCares/Blue
%20Light%20Impact%20in%20Children.pdf

https://www.who.int/uv/faq/uvhealtfac/en/index3.html

A lot more studies that you can find. Typical the ones that say it’s safe are talking about pc screens and phones. The lamps we use are producing several magnitudes of order more light than PC screens. In the aquarium world we are dealing with huge amounts of blue light.

( BTW sorry for the orginal screwed up post, Lol that what happens when you post at 2am while in bed half asleep. )

 

[Ron Reefman]

I'd like to read what @Dana Riddle has to say about this.

 

[32423535]

In all my review for Hybrid LED + T5 I always recommend the Super Actinic, every single time. It fill a gap that most LED don't have.

I don't have personal data (not a scientific) but I've always seen some corals react positively to it and a shift of color also but it always depends on the type of corals.

My mantra is if the Sun does it in the ocean, so should we.

Extremely curious to see expert answering this question.

 

[Bpb]

https://www.aoa.org/Documents/OptometryCares/Blue
%20Light%20Impact%20in%20Children.pdf

https://www.who.int/uv/faq/uvhealtfac/en/index3.html

A lot more studies that you can find. Typical the ones that say it’s safe are talking about pc screens and phones. The lamps we use are producing several magitudes of order less light than aquarium lighting.
In the aquarium world we are dealing with bug dose

Oh I’m well aware high energy photons causing cataracts. I wasn’t arguing that. I was simply saying eye tissue is not coral tissue. Saying “if it’s bad for our eyes, it is bad for corals” is like saying “since it destroys our eyes permanently, it must destroy a corals ability to photosynthesize”.

 

[piranhaman00]

Oh I’m well aware high energy photons causing cataracts. I wasn’t arguing that. I was simply saying eye tissue is not coral tissue. Saying “if it’s bad for our eyes, it is bad for corals” is like saying “since it destroys our eyes permanently, it must destroy a corals ability to photosynthesize”.

That’s not what @robbyg is meaning. He is simply stating these lights are bad for your eyes.

If you have children running around staring up at the tank and looking directly at the leds at the same time they are damaging their eyes. Nothing to do with coral. If there not needed for coral then don’t risk your eyes. And weigh the risks if they are “optional” wavelengths.

 

[Bpb]

That’s not what @robbyg is meaning. He is simply stating these lights are bad for your eyes.

If you have children running around staring up at the tank and looking directly at the leds at the same time they are damaging their eyes. Nothing to do with coral. If there not needed for coral then don’t risk your eyes. And weigh the risks if they are “optional” wavelengths.

Ah fair enough. I see the point from that angle. I feel safe enough that those wavelengths are attenuated sufficiently through the water and glass of the tank. Those of you who have lots of violet and UV lights hanging over the tank and don’t use a canopy may be concerned. I use a canopy so I almost never get direct line of sight view of my lights.

 

[Dana Riddle]

Here's an action spectrum for a Favia coral. Unfortunately, I did not include radiation below 400nm, although chlorophylls a and c2 can absorb radiation down to about 350nm. As a footnote chlorophyll a has a shoulder abosrbance at ~383nm. As for coloration, there are only two or three fluorescent pigments that are maximally excited by UV-A/violet radiation. As for coloration, In some cases, this radiation will be beneficial. In photosynthesis, it will be helpful. Is it necessary - no. We can ignore successful reef tanks that have no (or very little) UV-A/violet light.
There is some concern that violet/blue light is harmful to humans' eyes. I'm not an ophthomologist, but I can say that the dose of UV/violet/blue light at noon on a cloudless day could be more than what we'll be exposed to in most aquarium situations. In all my years of keeping marine tanks, I've only seen one fish go blind. As for protection against UV light, many fishes accumulate sunscreens in their eyes through diet - they cannot make it themselves, the pathway for making UV sunscreens is found only in plants.