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I have a Coralife Aqualight 150w HQI ballast. I'm currently running at 14000K bulb, but I want the color of my corals to pop more so I'm thinking about upgrading the bulb to a 20000K. This is probably a stupid question, but will my ballast work with a 20000K? I was thinking of getting either the Phoenix 20000K or the Radium 20000K. Is one more blue than the other? If you're running either one of them, I would greatly appreciate pictures so I can see myself how blue they are. Also, would a 150w MH 20000K grow corals faster than at 14000K? I've heard corals grow faster with bulbs closer to natural sunlight.


TIA :)

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20k will grow most corals slower. That is why many people go with 10k for growth and get T5's for actinic supplementation.


Proper lighting in a saltwater coral reef tank is probably the most important aspect for a well-balanced and thriving environment. Corals have specific needs in color temperature, or Kelvin (K) rating, to sustain life. Both 10K and 20K lights have advantages and disadvantages.


K Ratings

1. Midday sunlight on the surface of saltwater over a shallow coral reef has a K rating of 6500 or 6.5K. On the color spectrum, it is slightly on the blue side. A higher K rating equals a bluer wavelength, and a lower K rating equals a yellower wavelength.

10K Bulbs

2. Bulbs that are 10K are bluer than the optimal 6500 temperature and provide adequate energy, but coral growth with 10K bulbs is somewhat slower. The 10K bulbs also are not as yellow, however, and appear brighter, making the tank more visually appealing.

20K Bulbs

3. Bulbs that are 20K are darker blue and beneficial to deeper saltwater soft coral, mimicking the sunlight at greater depths. Their darker blue color also serves to bring out the fluorescent pigments of the coral, creating what can be considered a breathtaking visual experience. Shallow saltwater corals do not benefit from 20K bulbs, however, and have little or no growth with them.


4. Using a mixture of lights is recommended. They should be visually satisfying while maintaining a balanced system.


source: http://www.ehow.com/facts_6789087_10k-20k-...eef-lights.html

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I think I might stick with 14000K until everything in the tank is overgrown, then switch to 20000K for colour. Thanks. :)

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If you're still using the original bulb, you'll probably notice a lot of difference just by switching to a Phoenix 14,000K. The Coralife bulb is not that great.

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If you're still using the original bulb, you'll probably notice a lot of difference just by switching to a Phoenix 14,000K. The Coralife bulb is not that great.


Will it grow the corals faster?

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Isnt 12k supposed to be the closest to actual sunlight? To my understanding the higher you go from there the blue'r the light! Correct?



The K rating from the sunlight the corals get is different depending on the depth. 6.5k is the closest to actual sunlight near the surface of the water.

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From my years of experience if you really want your coral colors to "pop" you will pretty much need to use florescent actintics of some sort. Using a high kelvin MH just makes eveything purple.

I have favored MH for years because I like the shimmer. It also was cutting-edge when I started. I lived in Florida most of my life and spent alot of time in the shallow water so I prefer to use 10k metal halides with no actinticts. To me that most accurately matches what I saw those years in the water. But I digress....

Anyhow, I have had alot of different lighting set ups and to me the best "pop" was using a couple of URI 110watt 48" VHO bulbs set up in a dawn-dusk effect with my MH. Then I could see the "real" color of the ocean when the halides were on, but in the morning and evening I could see the crazy colors of the corals come out under the actintic. I really miss that set up alot and often wonder why I ever changed. :(

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