Recently new lighting that actually was originally developed in Europe, made their appearance in the US markets. I am referring, specifically, to the 10 000 Kelvin degree metal halide lights. Although the first ones that became available were European, newer ones are now made in the USA as well and sold by various companies. And, yes indeed, there are 20 000 Kelvin degree ones too, but those are covered in another article.
Whereas most hobbyists who were using metal halides already, were lighting their aquariums with either 5500 Kelvin, 6 000 Kelvin or 6500 Kelvin degree lights, the introduction of these new lights has sort of brought yet another twist to the lighting issue and makes yet another series of lights available to the hobbyist (as if lighting a reef tank was not complicated a subject enough already).
I have tested both the 10 000 Kelvin and the 20 000 Kelvin lights and would like to give you my first impressions on the 10 000 Kelvin degree oens, based on about 3 months of running these new lighting systems:
- The 10 K Kelvin degree lights are much more "blue" than any of the others I have mentioned. The color, though, is very pleasing to the eye. Because of the fact that is strong lighting, if the surface of the tank's water is moving, you will see ripple lighting inside your tank. This gives the tank a very natural look.
- Since they are so "blue", there is in my opinion, little need to supplement this type of lighting with actinic bulbs, although doing so before and after the photoperiod, for perhaps one hour each time, is not wrong and can be done without any ill effects. On the other hand, I have not observed any major benefits from doing so.
- I had actinic bulbs come on before the halides lit up, and did so for one hour. Then when the halides lit up, the actinics went off. At the end of the photoperiod they would go on as soon as the metal halides went off and would remain on for just one hour.
- Because of the cost of these bulbs and because they need different ballasts (transformers) you may wish to keep your present lighting system and replace only one of your present lights with a 10 000 Kelvin degree one. That would be a good way to start up reaping the benefits of these new lights without incurring a major expense. Do figure on around 400.00 dollars though for such a 175 watt setup.
- Of course, if you can replace "all" your lighting equipment with 10 K Kelvin bulbs you will get all of the benefits from this new and very intense white/blueish lighting.
- The results obtained with these bulbs certainly surpass the ones obtained with lower Kelvin degree bulbs. All corals open up more, although there are some exceptions. Not all of them react positively.
- Depending on where your corals came from, certain types (for instance Elegance and Bubble) may react negatively to this lighting, unless they are introduced to it gradually or unless they came from ocean/reef areas where the lighting was intense also.
- To do so you would not run the new lights for there full cycle right from the start, but you would sart with only a few hours a day and then gradually build up the lighting period every two to three days.
- Introducing the new lighting in this manner give the corals a chance to adapt to it without undue stress, and without bleaching or expelling their zooxanthellae.
- All corals that require intense lighting, and clams, do much much better under 10 K Kelvin lighting.
- Keep in mind that this lighting gives off a lot of heat and that if a hood (canope) is used, it should be very well vented. Several muffin fans should be present to extract the heat.
- Do not bring the lights too close to the water level unless you have a real deep tank. If you do bring the lights close, you can only put corals that require real strong light towards the top of the tank.
- Anemones seem to like this lighting a great deal. They definitely open up a lot more.
- Fish are not bothered by the lights at all.
- Before you decide on the change-over, calculate the costs you will incur as these lights are expensive. The cost of running them can be substantial too, especially if you need high wattage types. Presently the lights are available in 175, 250, 400 and even 1000 watts.
- I run my 10 000 Kelvin degree lights over a show tank, approximately 500 gallons in size, and use three 400 watt lights. Two are on for the full photoperiod of 10 hours, and one is on for 1.5 hours during the middle of the photoperiod.
- The change over from 5500 Kelvin to 10 000 Kelvin took a total of about 2 weeks to complete.
- No animals reacted negatively, but I did have to move a few corals around so they would not get the full intensity all the time. Elegance coral seemed especially sensitive to too high a lighting intensity.
- The more the coral relies on zooxanthellae for feeding, the better it will do under this type of lighting. All mushrooms, for instance, do much better and have started multiplying at a faster rate than they were before the installation of these new lights.
Overall, the conclusion I drew, after running these lights for three months, is that these lights are definitely worth acquiring even if their price is relatively high.
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