which is better 20000K or 10000K?

Steven0000 · 05/01/2007, 07:13 AM

i have a 20g tank and i would like to add a nice metal halide light fixture.

my ballast can use up to 250 watts
i was planning on getting a 175 watt bulb, but what i the difference in kelvin on the bulbs? which is better?

any information is appreciated

Kaos · 05/01/2007, 07:34 AM

What kind of ballast is it? All the MH ballast I know of are watt specific. Which means if it's a 175w ballast it will only run 175w bulbs and the same for a 250w ballast.

The kelvin rating is the color of the bulb. The lower the kelvin (6500k) the more yellow the bulb appears. The higher the kelvin (20000k) the more blue the bulb appears. Most people try for either a more white appearance (10000k) or more blue (14000-20000k). It' really personal prefence. But the higher the kelvin rating the less intensity (PAR) the bulb has. But w/ that much light over a 20gal. you are not really going to need a whole lot of intensity.

If it were me I would shoot for something in the 12000K-14000k range. This will give plenty of light to corals and should produce a nice color.

Steven0000 · 05/01/2007, 07:44 AM

how about a 250 watt?

Kaos · 05/01/2007, 08:04 AM

Quote:

Originally posted by Steven0000
how about a 250 watt?

The 250w will be the same as my first post but w/ more intensity (PAR). That is going to be allot of light on a shallow 20gal.

anguswu · 05/01/2007, 08:45 AM

If you are not planning on the SPS, you don't have to get to 250W. For most corals, 150W is enought for 20g and 14000k is good in color.

steelerguy · 05/01/2007, 01:50 PM

Which is better, chocolate ice cream or vanilla? A very subjective question indeed. It really is a matter of personal preference and how you want your tank to look.

In general, for a given wattage, a 10000k bulb will produce more PAR then a 20000k bulb. This might mean your corals will grow better but maybe not, depends on the coral and a lot of other factors. If you are going to also have actinic supplementation you may not want all that blue you would get with a 20000k and might consider a 10000k. Maybe you want some blue and you can go with a 12000k or 14000k or 15000k... As you can see, lot's of choices and is basically what you prefer.

(My fixture came with 2 x 150W 10000k halides with 2 x 39W T5 420 nm and 2 x 39 W 460 nm actinic lights. I am going to stick with that unless I want it a little bluer and then I will go with Phoenix 14000 K most likely.)

Rosseau · 05/01/2007, 02:03 PM

I prefer vanilla - but that's just my opinion.

Jadams · 05/01/2007, 02:55 PM

I would simply go with a 14k bulb. But thats just my opinion. I personally like the range and coloration it gives.

Let us know when you make a purchase as to what you decided to go with.

Best of luck!

Steven0000 · 05/01/2007, 03:17 PM

thank you for all your opinions and help

i have decided on a bulb with a higher kelvin rating
(i like blue more)

but, do you think a 250 watt mh bulb would be too much for a 20g?
(i only have a 250 watt fixture)

oldreefer76 · 05/01/2007, 07:04 PM

I have 175w on a 15g 12" off the surface and am thinking of going 250w but then again I am an SPS nut with 1200gph in the same tank

TTLamb · 05/02/2007, 07:17 AM

well depends on what type of things your going to have in your tank, usually sps corals will react better to 14000 k lighting for growing (persoally i think 10000 is a dumb idea, i go with 20000k on all of my tanks

TTLamb · 05/02/2007, 07:17 AM

well depends on what type of things your going to have in your tank, usually sps corals will react better to 14000 k lighting for growing (persoally i think 10000 is a dumb idea, i go with 20000k on all of my tanks) dont got with 10000k!

05/01/2007, 07:13 AM	#1
Steven0000 Registered Member Join Date: May 2006 Location: Atlanta, Ga Posts: 522	which is better 20000K or 10000K? i have a 20g tank and i would like to add a nice metal halide light fixture. my ballast can use up to 250 watts i was planning on getting a 175 watt bulb, but what i the difference in kelvin on the bulbs? which is better? any information is appreciated

05/01/2007, 07:34 AM	#2
Kaos "Lurker" Join Date: Jul 2002 Posts: 2,131	What kind of ballast is it? All the MH ballast I know of are watt specific. Which means if it's a 175w ballast it will only run 175w bulbs and the same for a 250w ballast. The kelvin rating is the color of the bulb. The lower the kelvin (6500k) the more yellow the bulb appears. The higher the kelvin (20000k) the more blue the bulb appears. Most people try for either a more white appearance (10000k) or more blue (14000-20000k). It' really personal prefence. But the higher the kelvin rating the less intensity (PAR) the bulb has. But w/ that much light over a 20gal. you are not really going to need a whole lot of intensity. If it were me I would shoot for something in the 12000K-14000k range. This will give plenty of light to corals and should produce a nice color. __________________ Ordinary people are the ones scared to be themselves.

05/01/2007, 02:03 PM	#7
Rosseau Registered Member Join Date: Dec 2006 Location: Kingston, Ontario Posts: 2,049	I prefer vanilla - but that's just my opinion. __________________ Still fighting entropy.

05/01/2007, 02:55 PM	#8
Jadams Registered Member Join Date: Dec 2005 Posts: 4,475	I would simply go with a 14k bulb. But thats just my opinion. I personally like the range and coloration it gives. Let us know when you make a purchase as to what you decided to go with. Best of luck! __________________ Jeremy

05/01/2007, 07:04 PM	#10
oldreefer76 Registered Member Join Date: May 2006 Location: Fairview Park Ohio Posts: 2,452	I have 175w on a 15g 12" off the surface and am thinking of going 250w but then again I am an SPS nut with 1200gph in the same tank __________________ 15G and working on getting better Current Tank Info: 15G and building

05/01/2007, 07:44 AM	#3
Steven0000 Registered Member Join Date: May 2006 Location: Atlanta, Ga Posts: 522	how about a 250 watt?

05/01/2007, 08:45 AM	#5
anguswu Registered Member Join Date: Dec 2006 Location: Taiwan Posts: 596	If you are not planning on the SPS, you don't have to get to 250W. For most corals, 150W is enought for 20g and 14000k is good in color.

05/01/2007, 01:50 PM	#6
steelerguy Registered Member Join Date: Jan 2007 Location: Stony Brook, NY Posts: 263	Which is better, chocolate ice cream or vanilla? A very subjective question indeed. It really is a matter of personal preference and how you want your tank to look. In general, for a given wattage, a 10000k bulb will produce more PAR then a 20000k bulb. This might mean your corals will grow better but maybe not, depends on the coral and a lot of other factors. If you are going to also have actinic supplementation you may not want all that blue you would get with a 20000k and might consider a 10000k. Maybe you want some blue and you can go with a 12000k or 14000k or 15000k... As you can see, lot's of choices and is basically what you prefer. (My fixture came with 2 x 150W 10000k halides with 2 x 39W T5 420 nm and 2 x 39 W 460 nm actinic lights. I am going to stick with that unless I want it a little bluer and then I will go with Phoenix 14000 K most likely.)

05/01/2007, 03:17 PM	#9
Steven0000 Registered Member Join Date: May 2006 Location: Atlanta, Ga Posts: 522	thank you for all your opinions and help i have decided on a bulb with a higher kelvin rating (i like blue more) but, do you think a 250 watt mh bulb would be too much for a 20g? (i only have a 250 watt fixture)

05/02/2007, 07:17 AM	#11
TTLamb Registered Member Join Date: Dec 2005 Location: Storrs CT Posts: 105	well depends on what type of things your going to have in your tank, usually sps corals will react better to 14000 k lighting for growing (persoally i think 10000 is a dumb idea, i go with 20000k on all of my tanks