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Does that include looking at the fact that certain types of wavelength provided in greater amounts, can result in the same effect as other wavelengths provided in far lesser amounts. What I mean is that one can achieve the same result by providing high amounts of PAR using a bulb that emits more of a particular desirable wavelength that is high in the wavelength corals can utilize.
Yes that is correct and several studies have been done in this area (with sunlight I need to add) that indicate that the type of radiation we should provide is the one that corals can indeed utilize and, in addition, ensuring that we provide enough quantity of such radiation. This has an impact too on pigmentation of corals, which is another area that we are looking at at Aquatic Wildlife. I will have some data available on this in the near future as I continue to monitor what exact wavelengths provide the kind of PAR that corals need for growth and also for pigmentation.
Pigmentation is an issue with both LPS corals and SPS corals but much more so with the latter. I have had excellent results with some of the testing I have done, applying and providing what I have found to be the wavelengths that promote faster and better or more intense pigmentation. I need to do some more work in this area and will then release the data.
Intensity or brightness is not an important factor if one provides the wrong wavelengths, even in large amounts. The key to success is to utilize lighting sources that emit the desirable wavelengths and those are the PAR ones. Anything that falls outside of that range is really of no use to corals and will not promote growth or coloration.
To be able to conduct research in this area it is important to be able to have a standard that one can use across the board when looking at different types of lighting. PAR is definitely such a standard and will, hopefully be used more and more by hobbyists as well, not just researchers.
Is this research directed more specifically to SPS type corals or can this be applied to LPS corals as well.
It really applies to all types of corals but the research we are conducting now is more geared towards the SPS types as they seem to develop more coloration when exposed to light sources with the right PAR levels. We will be looking at LPS corals as well of course as many hobbyists tend to focus their efforts on such corals. Providing them with data based on research in that area is therefore important to us as well. As I continue my research I will be able to make recommendations in those areas as well.
It does remain a fact though that if one wants color in an aquarium that it will more than likely come from the presence of SPS corals and to a lesser degree and with some exceptions (Elegance for instance) from LPS corals.
Because of the large number of species of corals on the market and the large array of bulbs being offered, what kind of advice would you offer to hobbyists in terms of what lighting to use.
I would recommend that the hobbyist use the 6500 Kelvin degree bulbs. The longevity of these bulbs appears to be pretty good and they develop a good deal of PAR. We are using those in our research facility and many corals really get magnificent coloration under these bulbs. If the hobbyist wants to experiment with the 10K and 20k Kelvin degree ones, they can certainly do so but it is my strong belief based on the research that I have done and am continuing to do that corals can be kept under 6500 Kelvin degree bulbs with great success and with real nice colors developing.
What is your feeling in this respect with regard to VHO bulbs?
Yes those bulbs develop a good deal of PAR and if the hobbyist want to keep LPS corals that is certainly a bulb to consider, providing enough of them are used. They can certainly have success with those bulbs and would be a good bulb to begin with. The results obtained with 6500 K ones though are far better and a larger amount of PAR is emitted with the beneficial consequences that go hand in hand with this.
Although you rate them as good, you do feel that they are not the best way to go, is that correct?
Yes that is indeed so. They do not develop anywhere near the amount of PAR developed by Metal Halides. Even though PAR is better than with other bulbs, MH ones produces a far greater amount and result in better success with coral growth and coloration.
Since we are talking about MH bulbs, quite some time ago, over a decade really, Osram HQI's used to be a popular bulb. Have you experimented with those types as well.
Yes I have looked at those too and although they produce a great deal of PAR, they produce a great deal of ultraviolet radiation too. If the hobbyist wants to use those he or she can do so but a shield will need to be used to filter out the UV. I would recommend the use of Plexiglass UF-4 to eliminate the unwanted UV radiation. They are excellent bulbs or light sources but because of the large amount of UV produced the hobbyist must take precautions there and definitely use shields to filter out the noxious UV.
Are you saying that what we have adhered to for some time, to be more specific, that we need some UV, may not be entirely correct and that UV is not all that important in reality.
Yes that is correct. Our research indicates that any wavelength below 380 nanometers is not desirable and is not required for coral growth and coral coloration.
Would that exclude the use of Actinic O3 bulbs which are quite popular among hobbyists.
Actinic O3's actually produce very little UV radiation. I would recommend that bulb if the hobbyist wants to provide more blue, for instance, in conjunction with a 6500 Kelvin degree bulb.
Would it be a good idea then to use Actinic O3 and if so for what corals would that apply?
It is in my opinion not necessary to do so but a lot of hobbyists like the additional blue that these bulbs provide when used with 6500 K MH ones. It is in my opinion a matter of personal preference and can be used for both LPS and SPS corals but, as I indicated, it is not really necessary.
Would you say that hobbyists use O3 bulbs because just about any book they open that deals with lighting tells them to do so. In a way they are led to believe that these bulbs are necessary because the literature stresses their use so much.
Our research indicates that they are not really necessary and that when used they mainly are because of the perceived aesthetic value they bring to the aquarium. From a PAR standpoint they are, based on my findings in regard to growth and coloration, not necessary but hobbyists can certainly use them if they feel so inclined.
It is interesting to note Dana, that I have never been an advocate of using O3 type bulbs, and you seem to confirm that what I recommended purely based on observation of corals, now pans out in terms of research.
Yes your early observations were indeed correct, and we have had that information for years but have only now through research been able to demonstrate that what you were writing was indeed correct. I have been a avid reader of your writings and find that in many areas you have certainly set the stage for what we can now prove through testing and research.
Thank you Dana, this concludes the portion of the interview dealing strictly with lighting. The next area I would like to get into is recommendations to hobbyists who keep, or plan to keep, SPS corals.
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