How many "k"?

damselsrck

damselsrck

Member
I am looking into buying a light, and the seller has the option of choosing how many "k" I want...the choices are:
10k
15k
20k
Is more better? What exactly does this stand for?
 
reefnut

reefnut

Active Member
That's an interesting graft sharkbait9.
damselsrck, what type of lights are you buying??
 
dogstar

dogstar

Active Member
I always like the look of around 14K myself, Depends on what you like and if the livestock requires something lower, Dont know of any thing that needs anything higher, that would be a personal preferance.
 
reefnut

reefnut

Active Member
I agree with the above... 10k MHs with actinic VHOs, PCs or HOs.
Something more to confuse the decision. The way the bulb actually looks and the PAR it produces also has a lot to do with the bulb you buy and the ballast you are running. The best way to decide IMO is to look at friend's tanks. Second best would be looking for pictures and finding out what lighting they run.
Just for further confusion... if we are talking about MHs the general rule for most bulbs... the higher the Kelvin the lower the PAR output. I have ran only 10k and 20k and I had better growth with the 10k + Actinics.
 
shnabbles

shnabbles

Member
I could be wrong, but i think the lower K's give corals more growth, where as the higher K's 15-20k are more for looks and less for growth... My 20k's now give off a blueish glow, im looking to move to 10k
 
rick58

rick58

Member
Over the years the only noticeable difference in growth speed due to lighting changes (differences in PAR) I've experienced have been for some of my SPS (some acros). Otherwise, nothing noticeable. Personally, I wish I could find a light that would encourage my corals to stay the same size - too much growth can be a real pain. Unfortunatly for me my wife did not care for the 'blue' look of my 20k lights and prefers the white look of my Iwasaki 6500k bulbs. Go figure.
 
sharkbait9

sharkbait9

Active Member
Originally Posted by ReefNut
That's an interesting graft sharkbait9.
damselsrck, what type of lights are you buying??
Yeah I thought so. When i was trying to explain for a couple of guys I work with about the Mh lights used in fish tanks and Mh lights used in the shop with the different K rate. Some people need pictures to help them understand. So I kept the pic for further explanations with others who need help. I thought it helps better to see on or about where color will be when changing k rated bulbs
 
damselsrck

damselsrck

Member
The light is a metal halide with pc's...here are the choices:
Metal halide bulb included free- please specify which you prefer - we have 10k, 15k or 20k
Power Compact bulb included free- We have 10k, actinic, 50.50 and 6500k bulbs available for the 55 watt power compact - please specify the bulbs you would like in your payment.
Does anyone have a combination of any of these? If so, could you post a pic?
I'm leaning toward a 10k metal halide bulb, what would be the best pc to pair with this?
 
moby

moby

Member
Personally I would mix the bluer PC with the whiter MH to avoid getting that yellowish tint you sometimes see. JMO.
Moby
 
damselsrck

damselsrck

Member
Ok, sorry, I'm such a noob, a bluer pc would be...? (same for the mh) sorry, that's why I posted here...I need to understand the light before I buy it...
 
moby

moby

Member
No problem!

The 15K Mh is what I use with the 50 50 actinic. this seems to give the "whitest" light without too much blue or too much yellow. But this is personal preference.
The higher the K the bluer the light is at depth. Remember as the water gets deeper the red is "filtered" out first since it is the shorter wavelength.
If you like the bluer light go with the 20K Mh and the 10K actinics. For less go with the 6500K actinics.
Easiest way is to look at others tanks and ask what lights they use.
Moby
 
moby

moby

Member
Aaaarrrgg!
Sorry that was me frustrated, the only digital camera I have at the moment is on my cell phone and isn't very good.

Maybe I should put that on my fathers day wish list. :thinking:
Moby
 
thirdchaos

thirdchaos

Member
For the best combination of color and growth, I would suggest the 10k metal halide with actinic power compacts.
The 10k bulb is bright and white/yellow (depending on the brand) but the actinic will add a nice blue look and bringing out color in you corals.
HTH,
Matt
 
damselsrck

damselsrck

Member
hmmm...nice looking tank! But I think it would be too blue for me (with the actinics). What would be just a little bit whiter than that last pic?
 
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