Watts vs. K

NewFishGirl · 12-10-2007, 01:59 PM

Hello, first let me say I am a lighting moron. I know next to nothing about watts and K (I don't even know what K means!).

I want to buy a replacement bulb for my boyfriend's tank (you know, Christmas and all). It's a metal halide fixture for a double ended bulb. It came with a 150 watt, 10,000 K bulb. Do I have to buy this exact same bulb (same company)?

Also, I've seen 150 watt, 6,500 K, 13,000 K, 14,000 K, etc. What does the K mean? Do I have to buy another 10,000 K? Should I?

I'd LOVE some help!

motorslave · 12-10-2007, 02:08 PM

K is Kelvin, which is the color "temperature" generally the lower the K the yellower the color, the higher the bluer. Generally 10K is considered to be white in color. BUT, different makers have slight variations in color. The bulb doesn't have to be from the same company but it does have to be the same wattage. If he was happy with the 10K Id stick with it. Some folks like the bluer high K bulbs. The lower the K the better the color for growth in coral as it is closer to the K of the sun. But, its less aesthetically pleasing and people get great growth with the higher K as there are so many other factors involved.
So, if he likes the color of the tank with 10K, get a 10K!

NewFishGirl · 12-10-2007, 02:25 PM

Quote:

Originally Posted by motorslave

K is Kelvin, which is the color "temperature" generally the lower the K the yellower the color, the higher the bluer. Generally 10K is considered to be white in color. BUT, different makers have slight variations in color. The bulb doesn't have to be from the same company but it does have to be the same wattage. If he was happy with the 10K Id stick with it. Some folks like the bluer high K bulbs. The lower the K the better the color for growth in coral as it is closer to the K of the sun. But, its less aesthetically pleasing and people get great growth with the higher K as there are so many other factors involved.
So, if he likes the color of the tank with 10K, get a 10K!

Thank you so much for that explanation. Well, I would say that the color of the light right now is too yellow looking. We are getting great coral growth, but I'd sacrifice some growth for a bluer color.

Is there much difference between 13,000 and 14,000 K?

Wiskey · 12-10-2007, 02:30 PM

Quote:

Originally Posted by motorslave

K is Kelvin, which is the color "temperature" generally the lower the K the yellower the color, the higher the bluer. Generally 10K is considered to be white in color. BUT, different makers have slight variations in color. The bulb doesn't have to be from the same company but it does have to be the same wattage. If he was happy with the 10K Id stick with it. Some folks like the bluer high K bulbs. The lower the K the better the color for growth in coral as it is closer to the K of the sun. But, its less aesthetically pleasing and people get great growth with the higher K as there are so many other factors involved.
So, if he likes the color of the tank with 10K, get a 10K!

Agreed

If he's happy with what he has, just buy him the exact same thing again

Higher K will (Generally but not always) put out far less light and look bluer. There are exceptions to every rule, for better data you can see Sanjay's light testing page,.. but I'm thinking you don't want anything that technical.

Whiskey

Wiskey · 12-10-2007, 02:31 PM

Quote:

Originally Posted by NewFishGirl

Thank you so much for that explanation. Well, I would say that the color of the light right now is too yellow looking. We are getting great coral growth, but I'd sacrifice some growth for a bluer color.

Is there much difference between 13,000 and 14,000 K?

There is a huge difference in some cases from Mfg to mfg of the same "K" rated bulb.

What bulbs specifically are you looking at?

Whiskey

NewFishGirl · 12-10-2007, 02:33 PM

The fixture came with this:

1x150W 10,000k PowerPaq MH

The fixture is a Current USA Outer Orbit.

Wiskey · 12-10-2007, 02:35 PM

Yes,... but you were talking about replacing it with something different,.. what bulb were you looking at?

Whiskey

NewFishGirl · 12-10-2007, 02:43 PM

The manufacturer makes the 150 watt bulb in 14,000 K (but it sounds sort of cheap at $49): http://www.marinedepot.com/ps_ViewIt...s~vendor~.html

Or, I also found these:
http://www.marinedepot.com/ps_ViewIt...s~vendor~.html

http://www.marinedepot.com/ps_ViewIt...s~vendor~.html

http://www.marinedepot.com/ps_ViewIt...s~vendor~.html

Any thoughts?

I've always thought our light was too yellow, so this would be a great chance to change things up a little.

mg · 12-10-2007, 02:51 PM

The megachrome is a great bulb. If you want something a little less expensive that a lot of people have been happy with, look at the Pheonix 14K bulbs as well.

saltysupply · 12-10-2007, 02:53 PM

some good brands are xm, giesemann, ushio etc...color temperature is personal preferance...the lower the temperature the more intensity for most bulbs

my personal fav is the XM 20k

mg · 12-10-2007, 03:03 PM

I just took a look at what little data Sanjay has generated for 150W bulbs. I looked at all electronic ballasts as that is what is in your fixture but not the exact one. It does show a trend of about half the amount of light being put out when going from 10K to 14K bulbs. What we look at for measurements is PAR (PPFD) or Photosynthetically available radiation. This is basically the amount of light available for the corals to use for photosynthesis. Sanjay tests out of water at a fixed distance so we can compare bulb and ballast performance. A 10K bulb puts our about 50-60 PPFD and a 14K bulb about 30-40 PPFD. If your boyfriend has a lot of stony corals, it might be something to consider as well.

What size tank is this? Really just looking for the height.
http://www.reeflightinginfo.arvixe.com/

Wiskey · 12-10-2007, 03:03 PM

Quote:

Originally Posted by NewFishGirl

The manufacturer makes the 150 watt bulb in 14,000 K (but it sounds sort of cheap at $49): http://www.marinedepot.com/ps_ViewItem~SearchStr~150%20Watt%2010%20000k%20Met al%20Halide%20bulb,150%20watt%20metal%20halide,Pow erPaq~action~view~idProduct~MB2665~idCategory~FILT BUMHDEHW~category~150_Watt_14000K_Metal_Halide_Bul b___Current_USA_Powerpaq__Double_Ended_Saltwater_A quarium_Supplies_Lighting_Bulbs_Metal_Halide_Doubl e_Ended_150_Watts~vendor~.html

Or, I also found these:
http://www.marinedepot.com/ps_ViewItem~SearchStr~150%20Watt%2010%20000k%20Met al%20Halide%20bulb,150%20watt%20metal%20halide,150 %20watt%20metal%20halide~action~view~idProduct~MB2 468~idCategory~FILTBUMHDEHW~category~150_Watt_1000 0K_Metal_Halide_Bulb___Blue_Life_SPS_(South_Pacifi c_Sunlight)__Double_Ended_Saltwater_Aquarium_Suppl ies_Lighting_Bulbs_Metal_Halide_Double_Ended_150_W atts~vendor~.html

http://www.marinedepot.com/ps_ViewItem~SearchStr~150%20Watt%2010%20000k%20Met al%20Halide%20bulb,150%20watt%20metal%20halide,150 %20watt%20metal%20halide~action~view~idProduct~MB2 612~idCategory~FILTBUMHDEHW~category~150_Watt_1300 0K_Metal_Halide_Double_Ended___MegaChrome_Marine_S altwater_Aquarium_Supplies_Lighting_Bulbs_Metal_Ha lide_Double_Ended_150_Watts~vendor~.html

http://www.marinedepot.com/ps_ViewItem~SearchStr~150%20Watt%2010%20000k%20Met al%20Halide%20bulb,150%20watt%20metal%20halide,150 %20watt%20metal%20halide~action~view~idProduct~MB2 663~idCategory~FILTBUMHDEHW~category~150_Watt_1400 0K_Metal_Halide_Bulb___Ushio__Double_Ended_Saltwat er_Aquarium_Supplies_Lighting_Bulbs_Metal_Halide_D ouble_Ended_150_Watts~vendor~.html

Any thoughts?

I've always thought our light was too yellow, so this would be a great chance to change things up a little.

If you want a visual refrence I think Kelli's tank uses that first 14K

It's no secreate that I love 10K bulbs,.. there all I ever use, but if you want somethign bluer then the first one you list you can see,.. and I might also consider the second to last or last one,.. The one by "South pacific sunlight" I've never heard of the MFG.

Whiskey

NewFishGirl · 12-10-2007, 03:03 PM

Okay, I have another question. Will going up to 14,000 K affect my corals?

There is only one MH bulb (the 150 watt). We also have two 96 watt dual actinics on the fixture.

We have LPS (torch, bubble, candycane), shrooms and zoas. It's a 45 gallon bowfront (not tall).

Wiskey · 12-10-2007, 03:04 PM

Quote:

Originally Posted by mg

I just took a look at what little data Sanjay has generated for 150W bulbs. I looked at all electronic ballasts as that is what is in your fixture but not the exact one. It does show a trend of about half the amount of light being put out when going from 10K to 14K bulbs. What we look at for measurements is PAR (PPFD) or Photosynthetically available radiation. This is basically the amount of light available for the corals to use for photosynthesis. Sanjay tests out of water at a fixed distance so we can compare bulb and ballast performance. A 10K bulb puts our about 50-60 PPFD and a 14K bulb about 30-40 PPFD. If your boyfriend has a lot of stony corals, it might be something to consider as well.

What size tank is this? Really just looking for the height.
http://www.reeflightinginfo.arvixe.com/

This is very true,.. you are going to loose a WHOLE lot of light if you go with the 14K,.. it's why I always use 10K bulbs.

WHiskey

Wiskey · 12-10-2007, 03:06 PM

Quote:

Originally Posted by NewFishGirl

Okay, I have another question. Will going up to 14,000 K affect my corals?

There is only one MH bulb (the 150 watt). We also have two 96 watt dual actinics on the fixture.

We have LPS (torch, bubble, candycane), shrooms and zoas. It's a 45 gallon bowfront (not tall).

With those corals over a 45G (assuming 18" deep) you can go with whatever you want,..

I would get a 10K and replace the PC's with "Atinic Blue" rather than "True atinic",.. the tank would look much more blue, and you'll get about double the output out of the PC bulbs.

Whiskey