Color temperature

[AC-WEB]

I had bought some new 20k 175wx2 bulbs for my metal halide light system. The colors were bright, but I noticed my clove polyps looking very shriveled up. I changed these bulbs out for 14k 175wx2 and noticed a bluer color but my clove polyps and everything else seems happy. I had thought that the wattage of the bulbs made the biggest difference with coral, but is color temperature also that important?

AC-WEB

[James77]

Originally Posted by AC-WEB

I had bought some new 20k 175wx2 bulbs for my metal halide light system. The colors were bright, but I noticed my clove polyps looking very shriveled up. I changed these bulbs out for 14k 175wx2 and noticed a bluer color but my clove polyps and everything else seems happy. I had thought that the wattage of the bulbs made the biggest difference with coral, but is color temperature also that important?

AC-WEB

Color temperture and bulb-ballast combo, as well as bulb age, can affect the intensity of bulbs. If your old bulbs were very old, the new ones might be alot more intense, and can shock corals. The higher kelvin/bluer bulbs tend to be less intense than warmer colored lamps.

[blasterman789]

The higher kelvin/bluer bulbs tend to be less intense than warmer colored lamps.

Less intense to our eyes but not to coral.

20k halides throw most of their energy into deep blue, usually in a band from 440nm to 460nm. Then a smidge of near UV and a smattering of green, yellow and red to give them some balance. Most follow this formula.

14K halides throw a lot more light into spectrums other than far blue, which is why they appear brighter to our eyes, but might actually have less growth energy. PAR meters won't tell you the right story because most are designed to rank orange and red light which doesn't mean a darn thing to coral.

What AC-WEB ran into is a classic example of this. The 14k bulb has a better spread of spectral energy while the 20k blasts anything sensitive to blue light.

[AC-WEB]

Originally Posted by blasterman789

Less intense to our eyes but not to coral.

20k halides throw most of their energy into deep blue, usually in a band from 440nm to 460nm. Then a smidge of near UV and a smattering of green, yellow and red to give them some balance. Most follow this formula.

14K halides throw a lot more light into spectrums other than far blue, which is why they appear brighter to our eyes, but might actually have less growth energy. PAR meters won't tell you the right story because most are designed to rank orange and red light which doesn't mean a darn thing to coral.

What AC-WEB ran into is a classic example of this. The 14k bulb has a better spread of spectral energy while the 20k blasts anything sensitive to blue light.

This has been very interesting and helpful. I'm still a layman when it comes to the technical aspects of the lights, but am able to follow along a bit.

Thanks Again!