10k/20k bulbs...is higher Kelvin better?

[gexkko]

I currently have an odyssea 250 MH hood on my 29. the HQI bulb it has is from oddysea and is rated at 20k. I'm fairly sure that 20k means it outputs at a wavelength more able to penetrate water depth than 10k. However, does it have any real benefit or detriment to corals at shallower depths?
I don't know the technicalities, so I'm not sure if 20k = all the kelvin ranges up to and including 20k or just those around 20k. Any help to clarrify this would be much appreciated.

 

[bang guy]

20K means that the combination of all the wavelengths produces a color toward the blue end. Kelvin color doesn't really indicate much about the actual wavelengths of light emitted.
For example, a 6500K Iwasaki mercury vapor bulb produces more blue light than most 20,000K Metal halide bulbs.
In my opinion, buy the bulb that looks best to you and let the corals adapt to it.
The difference in water penetration ability of blue light vs yellow light is insignificant at the 2 - 3 foot depth of most aquariums.

 

[isistius]

Originally Posted by Bang Guy
In my opinion, buy the bulb that looks best to you and let the corals adapt to it.

i have 10,000k over my tank now. when i look through it the longs ways, the lights give off a yellow tint. i will be switching to 15,000k shortly. imo, they give off the best color.

 

[gexkko]

Ok, that helps. I'll just continue to use the 20k bulb that came with the hood since I already have it. The hood also has 2x65w actincs, so the aquarium has a lot of blue color in it. It makes my green bubble really glow really nicely

 

[isistius]

the actinics will do that for ya
***)

 

[jam marine]

i was in the same predicament recently,i just changed to 250 watt mh,i got some 10,000k lamps,called sunny day,which i have never heard of before,but strange enough,i have gotten some growth in the 2 months i have them on,but after much debate i have just ordered the hamilton 14,000 k bulbs,which i hope will give me some growth as well as the colour i am looking for.

 

[acrylic51]

You'll see more growth out of a 10k bulb then a 14k bulb......you would see most growth out of a 6500k bulb than a 10k as well....

 

[gexkko]

well, i have a small tank, so slower growth is actually better for me. I guess i'll stick with the 20k until its lifespan runs out.

 

[bang guy]

Originally Posted by Gexkko
well, i have a small tank, so slower growth is actually better for me. I guess i'll stick with the 20k until its lifespan runs out.
That's a big downside to 20,000K bulbs. The typical lifespan is about 6 months.

 

[gexkko]

Yeah, but I got the hood for a steal, so I'm not complaining. I'll just pick up a new bulb in about 5 months
Its kind of funny that all the lights in my appartment are energy saver lights. I do everything I can to conserve power and do my part and all that jazz, yet when it comes to my tank I have 380 watts of high-energy lighting, powerheads, heating, etc...

 

[dejaco]

Personally and IMO I reaaly like the look of 10000K MH lighting but I also run 160 (2) watt VHO actinic whites the combination looks like what I see when snorkeling! Oh yeah I am now frgging and selling to my local lfs this way!