10k 20k?

[CREEPIN]

whats the diffrences?
Thanks!!

[tippMANn98]

10k is more on the white side, and 20k has a bluer tinge to it...

[CREEPIN]

does it affect the coral/fish in anyway? if so, do you need a better lighting system to run these bulb...thinkin of buildin my bigger tank soon so i need to know what i am buyin..
Thanks!

[tippMANn98]

the only difference is the spectrum, and what it will look like to you...usually you combine a 10 k with an actinic 420/460 nm to make the "normal" look, All depends on what you plan on keeping. coral wise

[Octoman]

Just posted this on another thread...


Lighting the Reef Tank: A Primer for Beginners by Doug Wojtczak - Reefkeeping.com

"When it comes to metal halide color spectrum, there is no one general rule of thumb, but some general observations can be made. Many hobbyists use metal halide bulbs with a Kelvin rating of 6500, and these bulbs produce a warm yellow/white appearance that simulates the midday sun on a shallow reef. Bulbs of this color are well suited for high light demanding corals and clams. While hobbyists report great success using these bulbs, they often complain of their yellow appearance when used without supplemental actinic light. Another common bulb is the 10000-Kelvin bulb, which produces a white appearance with a slight hint of blue. Although many hobbyists have also had good results using these bulbs over most types of corals, some have noticed that coral growth rates are somewhat slower than those using 6500-Kelvin bulbs. Gaining much wider acceptance and use lately is the 20000-Kelvin bulb, often called a Radium, which has a blue colored appearance. These bulbs are better suited for deeper water soft corals and LPS, although many hobbyists have also had success using them over clams and SPS."

[tippMANn98]

u said what I couldnt fit into words....i wasnt sure on the 20k for deep water, i was gonna put that...but you eased my mind...thanks for that info Octoman

[kimoy]

10 K more on the white side and may be yellowish depending on the bulb and faster coral growth while 20K can become too blue and slow coral growth. No effect on the fish.

[CREEPIN]

so basicly 10k and actinic lights are the way to go?

[kathywithbirds]

I'm kinda gettin' into the SPS a little and they seem OK with my two 150w 14K halides but I also run the actinics all day too. The actinics come on earlier and off later. It's not a spectacular actinic bulb, coralife I think. So far so good. Can't say they're growing fast though. Bulbs are my next project so I'm following lighting threads.

[CREEPIN]

how about like one of every bulb lol?

[kathywithbirds]

I'd like to do that! But alas, finances and space prohibit massive bulb purchases

[Octoman]

I've got an actinic - on 12 hrs (10am-10pm)
10K and 14K - on for 10 hrs (11am-9pm)
6700 - on for 4 hrs (2pm-6pm)

[zy112]

A lot of it depends on what the reefer want. If your eyes like blue go with a higher kelvin bulb. Some par and intensity may be lost though and coral growth will be slightly sacrificed. Personally, I have run 10-15k bulbs with actinic supplementation. With no actinics, I would probably go with 20k's. Seems like the trend keeps going bluer.

[BigAl07]

I personally like bluer as well. I'm planning to go up well above 10h on my next bulbs.

[NATIVEVAMAN]

I have spent the last year and a half reading just about everything I can get my hands on with a strong emphis on lighting and here is some of what I have learned.The color temp of sunlight at the equator is 5745K.That is truly full pectrum light.From that point on all the way to 20000k the light becomes continually bluer.More than a few studies have been done to indicate that the best coral growth occurs near 6500k.This is logical because coral have evolved over millions of years growing under a 5745k light.The major problem with 6500k light is that it makes a tank look awful.Now 20000k light makes the tank look great almost everyone loves them.However the same articles say that 20000k light promotes the worst coral growth and generates the lowest par of any bulb on the market.20000k is so far from the natural enviornmental light that corals thrive in that it is logical that 20000k light would not promote very good growth.A happy medium of 10000 or 12000k with actinic supplimentation seems to be the answer.Most agree that at 14000k the bulbs are blue enough to stand alone (without actinic suplimentation).