Actinic useful for photosynthesis?

[sundancer]

I have read somewhere that actinic lamps just make things look pretty but actually does little for corals. What are your opinions on this? Do you think actinics produce much useable light for photosythetic aminals?

[hybridgenius]

No.

[gh0st]

It really depends on the corals you wish to keep. Every coral has a spectrum of light it is adapted for depending on how deep it grew.

Shallow water corals could usually care less about Actinics, while deeper water corals prefer a much more blue weighted light, so Actinic becomes more important for them.

Caflo's Coral Propagation book has a good deal of text dedicated to encouraging aquarists to find out how deep the coral is from, and trying to replicate the light it is used to in order to reduce stress and encourage health.

[barjam]

Actinic is one of if not the most active light frequencies for photosynthesis regardless of coral or depth.

http://www.life.uiuc.edu/govindjee/paper/fig5.gif

The myth of actinic not being usable light comes from how people tend to use actinic. If you supplement 500 watts of metal halide with 100 watts of T5 actinic you aren't adding very much to the total pool of light but if you are adding actinic to a T5 setup it is a substantial portion of the total light.

You could run 100% actinic over a tank and the corals would grow. Most T5 users do something close to this now with 80%+ coming from 420nm/450nm with a little green/yellow throw in for some lumens.

[barjam]

Shallow water corals could usually care less about Actinics, while deeper water corals prefer a much more blue weighted light, so Actinic becomes more important for them.

Shallow water corals see far, far, far more actinic light than deeper water corals because they see far more total light than these deep water corals. Yes water attenuates reds/yellows but it also attenuates the blues.

[tgreene]

I have a large aquaculture facility in my basement (roughly 1200g at this point), and I'm running 100% UV T5 Actinics and 20k Metal Halides.

While the skeletal growth rates may seem a bit slower, the tissue color and growth is insane... This is what's most important to me and my clients.

[sundancer]

I am running all 18K T5 in my tank now. I added a couple a actinics but don't care for the color but wonder if I will be shortchanging my corals on the blues? I also tried a switching in some 6700K just for kicks. With 20% 6700K I get much more lumens and a yellower light which I think resembles natural sunlight more closely but don't know what it will to to the corals long term.

[JediReefer]

Yes barjam is correct. I was also under the wrong impression.

http://archive.reefcentral.com/forum...readid=1270275

[rickh]

The maximum absorbency of Chlorophyll is 400-480 nm.
The shorter the wavelength, the higher the energy.
After full spectrum light passes through a few feet of sea water what's left?? Actinic.
R

[chadfarmer]

i know a guy that has a prop system with actinic white and actinic blue vho bulbs and nothing else and everything grows

[sundancer]

So it's mostly YES for actinics. Thank you all for your response.

[barjam]

I am running all 18K T5 in my tank now

What bulb specifically? I assume you referring to a blue plus type bulb with a 450nm peak. Lumens are for your eyes only, not the corals. You should be interested in par. Grim has done some par tests (search for the thread) that compares various bulbs so you can get idea what par has more par than another.

Actinic fluorescent bulbs always test low but in my opinion that is partially to blame on the meters used, even the licor meter does a poor job of measuring 420nm. If you take into account the meter issue along with the fact that corals like 420nm I personally group the par from a bulb like the UVL Super Actinic the same as a Blue plus and the Blue Plus is knocking on the daylight bulb's doors pretty hard.

[sundancer]

I am running Hagen Powerglo.