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What are the true benefits of actinics?


travisurfer

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TheL.C.Reefer

its not just about aestethics, actinic lighting provides around a 420nm wavelength that a lot of corals need to meet their zooxanthellae requirements. Which in turn "color up" the coral to their true color on the reef. For example, I run a 175 watt 10k metal halide setup with VHO actinics, One week my actinics went off and since the halides were the only things running, I lost a lot of pigment/color on my SPS and even some of my green polpyed leathers...After actinics were replaced and running the color eventually came back...

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Actinic's are a must for live corals. In fact most of the "white light" is for our viewing pleasure. Also while were on the subject, actinic bulbs need to be replaced more often than other spectrum bulbs.

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anyone? what about those that just run halides?? i have a 30" sunpod over my 20L 150W HQI 14K..does this bulb not provide enough blue for the corals?

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Undertheradar

The full range of PAR or visible light is from about 400 - 700nm. The 400nm range is borderline UV and the 700 is borderline IR. Green is around the 500nm range, and blue about 450nm. Actinic, or purple, is about 420nm.

 

Actinics are mostly for looks...but it depends on the bulb you are running them with. 20,000K bulbs have a huge spike in the 450nm blue range, and a good size one at the 450nm purple range. 14,000Ks have the huge blue spike at 450, but often lack a good 420nm range. Literally, the only diff between a cool blue radium (perhaps the bluest bulb around measured to be something more like 38,000K, is identical in output to a 14,000K pheonix in every respect except it also has a a large 450nm spike. This purple is what really gives the look of 'deep-blue-sea'.

 

Then there are the 10,000K bulbs, the Ushio being a favorite. Here's the kicker...they have a pretty flat light output across the spectrums...with a good amount of 420nm as well as a large amount of 420nm already (most 10,000Ks have more 450nm output than a 14,000K, its the lack of the warmer spectrums along with a strong 450nm spike that makes a 14,000K)! We just dont see it as much because of all the other warmer spectrums being put out by the 10,000K bulbs. So we often pair 10,000K bulbs with actinics. There is a problem with this for some. no matter how many actinics they add, they just dont get that 'deep blue sea look'...and its because they have combined a daylight halide with 420nm actinic, but no 450nm blue...so its like a day-purple look. This is why many prefer just using 20,000K bulbs. Or, what you do is not only have a couple actinics with your halides, but a couple aqua-blue bulbs as well. These have a more significant output then an actinic anyways as far as the corals are concerned...esp if you have T5s.

 

And then you have 6500K Iwasaki bulbs...despite being so yellow, they grow corals great! Why? Because if you look at their spectral graph, they have gobs and gobs of 420nm and 450nm light...more than any 10,000K....you just dont see it because of all the gobs of warmer light they put out.

 

BTW, in photosynthesis in plants, it seems blue light is for growth and red for budding. Now, for underwater corals, this changes because the water filters out red spectrums pretty fast, and there are other adaptations going on. Many forms of cyano can be caused when your 10,000K bulbs start to burn out because many forms of these algaes feed on IR light so they dont have to compete with other species for the rest of the spectrum. The research is being done as we speak, but so far there are 14 some odd types of symbiotic photosynthetic cells being found in corals, anemones, bacterias, etc. And my observation is that the blue spectrums are more important for corals...which makes sense considering thats what they would have in nature. This also means that an excess of yellow light could cause 'browning' and 'coral stunting'. IMO, light is not just light, and blue light is more important for photosynthesis, color, and growth in corals than any other. I can observe increased growth with bluer bulbs even though the overall output might be lower. I can 'burn' corals, or overexpose them until they brown out and stop growing with 10,000K light, but its almost impossible with 20,000Ks...even when I put two 400watt radiums over a 30breeder...the corals just keep on growing.

 

Ok, enough background.

 

Actinics are part looks, part growth. They are an example of a bulb with a very narrow output designed to suppliment in the 420nm spectrum. Now, at that, they are not 'needed' by anyone. I suppose the final solution to the question "are they for looks or growth" is really depending on what the user intends them for. They do have a PAR that corals respond to...but it is often insignificant compared to the gobs of light that a halide puts out...and so its mostly for looks then. But for someone who buys a 20,000K bulb, that actinic output that the bulb has might be for the 'deep-blue-sea' look, but also means significant growth. As for the add-on actinics adding up to more growth...well...it depends on how many you use. If you have at least 50% of your lighting in actinics...that is enough to mean growth.

 

Its just a bulb with a narrow output...thats all...looks vs. growth is up to who uses it.

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Undertheradar

I just wanted to add an example of 'looks' vs. 'growth'. On a custom installation I am working on, the main lighting will be provided by a large skylight, but for supplimental color we were going to put in four 1000watt 20,000K halides. Since then, my attitudes about T5 have changed, and we will instead do a huge installation of T5s...about 20-30 of the 48" bulbs in the blue plus (450nm blue) and 20-30 of the 48" bulbs in the actinic plus (420nm purple). This should suppliment the daylight to look alot like 10-20 feet under the sea. So the intent was for looks...in fact, we were considering just using blue tinted plexi in certain sections of the skylight to simply tint the light coming through... but in consideration, this could mean a very incomplete spectrum and lead to coral pigments that would be less than spectacular. So from that aspect, the actinic light does result in better looking corals.

 

Note that we will be using not just actinics but a large amount of blue plus. I find it very odd looking at a tank that is nothing but 10,000K and actinics. It looks incomplete to me because it lacks that blue spike...its just a huge warm looking light and purple....where's the blue?!?! You would never sind lighting like that in nature after all. I think more people should look into using an equal amount of blue bulbs as they run actinics. In the case of the 1500g tank above in Chicago, these blue T5 bulbs also happen to have a very strong PAR...so they arent just looks.

 

I have a friend who runs a 120g with two 250wattDE pendants at 10,000K, but also runs 4x54wattT5s...2 actinic 2 blueplus... this gives the tank almost a 20,000K look. His milliporas (hes a millipora freak...something like 20 varieties in there) and zoos all grow by the bucket. In the one year his 120 has been set up...his corals have outgrown it already.

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Undertheradar

Thanks guys (or gals just in case...dont want to offend the ladies). Im into this stuff, and my engineering background doesn't hurt of course. You spend enough time staring at spectral graphs of bulbs and talking with lighting engineers and you begin to see how easy it really all is. Its the marketing guys that confuse everything by wild claims of what they think a correct specification is...just to help sell a few more units...

 

Example: Aqualine 10,000K (labelled at 13,000K on the box) bulbs. They are among the yellower 10,000Ks out there...but AB tries to get around it by saying that they think they are like 13,000K...when they are really more like 8-9000K. They have perhaps the least amount of blue & purple in their spectrum (less than any other 10,000K I know of), and although they boast an impressive PAR...coral growth under them seems to be lacking. When I swapped out them for the 14,000K pheonix bulbs...my tanks finally came alive! And supposedly, the pheonix has a lower PAR.

 

This is where something called PUR comes in. PAR is Photosynthetic Available Radiation...but PUR is Photosynthetic Usable Radiation. PUR is what varies from coral to coral. Xenia might like warmer light, and grow fine under 10,000K only...but when you try growing something like Blue Tort, you had best have a little more blue. I never understood this because I have a friend that grows tort under 10,000Ks only and ends up with some very nice coloration and growth...where I had no such luck under my Aqualine 10,000Ks...and couldnt grow it well until I used 14,000Ks. Then I realized why. The 10,000Ks he was using (Ushio), might look similar, and be called 10,000Ks, but have some of the largest purple spikes of any 10,000K (so much, that if it werent for the lacking 420nm spike, the Ushio 10,000K would be a 20,000K. So marketing can be very confusing and misleading.

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Undertheradar

Do you want VHO, PC, T5? If thats open, then I would go with T5...depending on the length of the tank, I would do something like 40-50watts of actinic, and another 40-50watts of blue plus.

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Undertheradar

well, VHO and T5 start at 24", so that leaves you with PC bulbs...a mix of 420nm and 450nm bulbs (4x32watters perhaps). But a 15"x15" sounds kinda small for a 175 halide...perhaps the better way is just to pick a bluer bulb...like a 14,000K... so little to no supplimentation is needed.

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IMO opinion actinics are not needed at all....Ive seen many syytems out here in California with straight 6500K or 10K halides and they are doing awesome.

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Undertheradar

very true. As I pointed out above, the 6500K puts out more blue and purple than most 10,000Ks...and 10,000K's have almost the same actinic output as a 20,000K...its just that we dont see it because of all the green & warmer spectrums that cover it up. So, in this case, your use of actinics would be mostly for looks.

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well, VHO and T5 start at 24", so that leaves you with PC bulbs...a mix of 420nm and 450nm bulbs (4x32watters perhaps). But a 15"x15" sounds kinda small for a 175 halide...perhaps the better way is just to pick a bluer bulb...like a 14,000K... so little to no supplimentation is needed.

well i was going to get a 150w MH 10000K, i was just wondering if i needed to add more blue then what would i need

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Undertheradar

Semi_xAsian, A 10,000K is a pretty well balanced bulb. IMO, I like more blue, and some others like raptor might not. A 10,000K can stand on its own, but you might not find the colors you get to be as impressive. What size tank would this go on?

 

drowning, I had a reefsun system at one time (mogul base version of what you are considering). FWIW, I would go with the PFO mini-pendant instead. Better reflector, better ballast. A friend of mine uses a dual reefstar over his 120g. He started with 10,000Ks and 4x54wattT5s for his blue and actinic. It looked very nice, but recently, he swapped those out for Ushios, and then some kind of 12,000K bulb for more blue. His corals look better every step bluer he gets.

 

I like the hamilton 14,000K, but be warned, its PAR is not very competitive, and ist gives out alot of green it seems. Their 20,000Ks are nothing to write home about. FWIW, there are many other better bulbs out there that you should try to see if you cant get instead. Or, get the PFO setup.

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Under,

your info was of great value to me. I am getting a 70w DE MH for my 10g AGA and I have a choice of a couple bulbs. Do you have any info on the Astra Lux 14K bulb? I can get that bulb or the Ushio 10K, but I am not sure which has the better 420nm and 450nm. I would preffer to be able to use 1 32w PC for my dusk/dawn effect and not realy need atinic supplimantation. Thanks for your thoughts.

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