The truth on Actinic lighting

[ReefFan]

Ive heard many conflicting opinions on what actinic light does for an aquarium. I have just as many people saying its just for the sole purpose of our eyes and does nothing for coral or plant growth. But then I hear other people who I considered to be quite knowledgeable, say that macro algae growth is stimulated with it and its a light frequency vital for coral growth.

The reason I ask is cuz Im trying to find the ideal combination of 6 T5 bulbs above my 75 and wondering if I should add an actinic bulb to my planted tank, which is more of a large display refugium.

So can anyone say definitively whether or not Actinic light has any other purpose than simply making corals n such appear more colorful to us?

 

[anthony27]

I would also like to find the reason out to I have heard it is to make coraline gorw

 

[rgun2515]

I would also like to find the reason out to I have heard it is to make coraline gorw

I can say this for sure. You do not need Actinic lighting to grow coralline algae.
My sump is full of coralline, and I have no Actinic lighting in it.

I remember reading something a long time ago on reef central, but can?t recall exactly what it said. I think it helps out with coral growth.

 

[Reeftanker3295]

They put out UV lighting. Without the UV lighting, corals do not fluoresce or have the colors that they have with the UV lighting.

 

[JHOV2324]

2 ATI 12k Aqua Blue Special
2 ATI Blue Plus
2 UVL Super Actinic

These are the T-5 bulbs I use and recommend.....I've been running them with a regular Advanced Ballast which is subpar....and gives a more BLUEISH look...i now have an icecap ballast that will overdrive the bulbs and give a more crisp look.... Good Luck

 

[tosiek]

Its light, has a par rating, and provides a spectrum of light for your coral or anything in your tank. Its going to provide some sort of photosynthesis/growth for anything that uses light.

There are actinic bulbs that are junk bulbs painted blue for the "look" of actinics that won't do more than a reg household lightbulb will do and there are ones that are very good high spectrum/output for your tank to maximize growth/color. Some actinics provide better growth and color to your tank over others although not as noticable or varying as different MH pars and bulb brands would. Get something with a nice blue that you like for your tank and your set.

If anyone tells you otherwise tell them they are wrong (maybe with a negative comment followed degrading their reef knowledge) or to spend the 5-10$ on better bulbs and make those actinics useful.

 

[john90009]

yeah from what iv learned the vho atinics are way better then any t-5 actinic. iv never seen an t-5 actinic work as well ast a vho actinic- im putting vhos with my t-5.

 

[cmor1701d]

Actinic light (420 nm) promotes the growth of Zoaxanthellae algae.

 

[DREUTZ]

I've been looking at the stunner LED strips and there are two types of actinics: a 453 nm and a 403 nm. Does anyone know the difference in these numbers. Are they the wavelengths?

 

[anthony27]

ok I have 460 atinic bulb way different color then the 420 so what is the difference in the spectrum

 

[ming]

The OP says its for a PLANTED tank, so I'm assuming no corals. Actinics are NOT needed for a planted tank. If its only plants, I would advise getting bulbs somewhere between 6700-10k bulbs which produce the most PAR which plants use. Actinics produce less PAR which = less growth then say 10k bulbs. If there are corals in the tank, Actinics help the coral get more flourescent, otherwise you will have more brownish corals.

 

[jrobbins]

http://www.reefs.org/library/article/actinic_lighting.html

 

[noodleman]

any light that has a wavelength in the PAR range will promote growth. it just depends how much PAR is being given out of that bulb. The wavelengths are stated by the nanometers "nm"

 

[ReefFan]

Thats exactly what I have for the planted tank, one 10k T5, one 6700k T5. But i was thinking of adding more light to that tank. More important though I wanted a smart MT lighting combo that promotes growth more so than make it appealing to the viewer. Its just an experiment with growth at this point. If actinics are vital to the growth of corals then I will obviously add them in. But if the coral doesnt miss actinic spectrum lighting in the least, then I might as well maximize my par.

It seems the bottomline is pick a combination I enjoy and as long as theres enough lumens, the stuff will grow. BUt if growth rate was the ONLY concern, is actinic light even necissary?

If its not then it appears actinics fall under one category and one only, light that makes the objects it falls upon look nicer to us. You will sacrifice par but corals appear more colorful. IT doesnt promote growth in any other way than the limited par they add, nor does it make other coloration to naturally occur within the coral.

So if you were to cut, say a favia in half... place one half under a 6700k MH bulb, supplemented by 3 6700k T5 bulbs in one tank. The other half under the same MH bulb, but supplemented by 3 actinic T5 bulbs in another tank (same exact conditions). What might be the diffferences Id observe after a year if I moved both halves side by side under the same 10k light?

BTW the actinics id be using are Giesemann Act+ and Giesemann Pure Act, not junkys.

Lastly are there any types of coral that would show differences, exposed to the same lighting experiment?

IF I could find an answer on those two questions then this whole reef lighting issue would finally be wrapped up Actually I think i understand now after all your helpful replies, just wanted confirmation.

 

[ming]

If growth is the ONLY concern, then actinics aren't necessary.
But I do want to point out, after you grow them without actinics for a long while, switching your bulbs to actinics won't all of a sudden make brown corals colorful. It can take a long while before their colors show again.
Also, the 6700-10k bulbs have higher PAR which can bleach your corals if its a huge increase in PAR, and not all corals like too much light

 

[noodleman]

a 6700k bulb will have the same wave length as an actinic bulb and more, just look at the spectrual plots of the bulbs, it just appears to be yellow to our eyes from the other wavelengths mixed in there. An actinic bulb is made to only spike near the 420nm area.

actinic bulbs will make you corals mroe colorful becuase the wavelengths are shorter and near the UV range, so it's a defensive reaction by the coral to produce more flourescent protiens to shade themselves from the harmful wavelengths

 

[cowfish]

It seems the bottomline is pick a combination I enjoy and as long as theres enough lumens, the stuff will grow

Lumens are a "visual" measurement - how bright the light looks to the human eye. Lumens measurements have nothing to do with photosynthetic growth.

From what I've learned PAR may not be the Holy Grail of lighting since different corals use different wavelengths of light for photosynthesis. The farther from the water's surface the more certain wavelengths of light do not penetrate starting on the red end of the spectrum. Certain fish are a bright red color - In their natural habitat they are practically invisible because red doesn't show at that depth. Another example is that without proper filters and strobes, picture taken far from the water's surface always have a blue tint to them. Blue is the only light that penetrates that far down.

 

[SWITCH420]

http://www.americanaquariumproducts.com/Aquarium_Lighting.html

heres a great link about lighting

 

[prattreef]

I see no evidence that actinic light aids coral growth or health beyond adding more wattage to the system. It does certainly add to the reflective florescence of coral pigments and may induce production of certain pigmentation as well, but these are primarily aesthetic concerns for the aquarist.

I'd like to submit Sanjay's remarkable aquarium and my own less remarkable one as 2 examples of healthy, fast growing, SPS dominated mixed reefs that have never seen an actinic lamp since the day they were set up. I think both of us would add actinic supplementation for aesthetics, but neither of us feel the need to do so because of husbandry.

 

[ReefFan]

Awesome info guys. Thanks for all the intelligent perspectives on lighting. Going to check out that link now but I think I have a pretty good Idea how to best use the components I have for my intended results.

MR rocks