14K vs 20K

gspgretchen · 01/29/2008, 11:29 AM

When I order my 175 W MH bulbs I dont know which would be the best for softies and some sps/lps. I understand 20K is for deeper water specimens. This will be my first experience with stonies and MH lights, and I want to do it right.

oct2274 · 01/29/2008, 11:53 AM

20k is not for deeper water situation in the aquarium. a 20k bulb typically puts out less par then a lower temp bulb like a 10k or 14k. A 20k bulb will be more blue like the ocean would be a lower depth. If you are not going to be doing SPS I would consider a 20k bulb because you won't have to supplement the bulb to get good color typically. But at the same time you will have less output then a 14k or lower temp bulb. You will probably be able to do SPS in the very upper part of the aquarium with a 20k bulb.

oct2274 · 01/29/2008, 11:58 AM

if you are using a magnetic ballast, I believe the XM 20k is the brightest 20k. Do not even consider the XM 15k bulb because it has horrible output and believe it or not even the 20k has more output then it.

DarG · 01/29/2008, 12:10 PM

The color temp, K ratings, are very often nothing more than marketing numbers. You have to be careful. There are 15000K bulbs that actually measure 10000K and below. Some 15000K bulbs measure 20000K and over. Some 10000K's may measure closer to 15000K or actually closer to 6000K. Some 20000K bulbs may really be 15000K. The rated color temp. is very often not the true color of the bulb. Best to look at Sanjays site which is linked in the top sticky thread on this lighting forum. He has measured many of the bulbs and you can see their true color temperature as well as PAR. Make sure you pick the ballast type that you plan to use because the ballast type impacts the PAR as well as the color to some extent.

BTW, the Iwasaki 15000K 175 watt bulb is one of the better bulbs on the market. Par is comparable to alot of 250 watt bulbs and color is close to the 15000K rating.

gspgretchen · 01/29/2008, 02:06 PM

I have an Advance M57 ballast 175 W. So basically the 20000K with be more pleasing to the eye, but less output. Then how would a 6500K (I used to run 6500K NO bulbs for my softies, they did great) compare.

01/29/2008, 11:29 AM	#1
gspgretchen Registered Member Join Date: May 2002 Location: Lincoln NE Posts: 148	14K vs 20K When I order my 175 W MH bulbs I dont know which would be the best for softies and some sps/lps. I understand 20K is for deeper water specimens. This will be my first experience with stonies and MH lights, and I want to do it right. __________________ "Boys, oh boys... I think he's come back for his noon feeding." Hooper (Jaws) Current Tank Info: 75g reef with twin 175MH/actinic Hamilton lights

01/29/2008, 02:06 PM	#5
gspgretchen Registered Member Join Date: May 2002 Location: Lincoln NE Posts: 148	I have an Advance M57 ballast 175 W. So basically the 20000K with be more pleasing to the eye, but less output. Then how would a 6500K (I used to run 6500K NO bulbs for my softies, they did great) compare. __________________ "Boys, oh boys... I think he's come back for his noon feeding." Hooper (Jaws) Current Tank Info: 75g reef with twin 175MH/actinic Hamilton lights

01/29/2008, 11:53 AM	#2
oct2274 Registered Member Join Date: Feb 2006 Location: Plano, TX Posts: 2,347	20k is not for deeper water situation in the aquarium. a 20k bulb typically puts out less par then a lower temp bulb like a 10k or 14k. A 20k bulb will be more blue like the ocean would be a lower depth. If you are not going to be doing SPS I would consider a 20k bulb because you won't have to supplement the bulb to get good color typically. But at the same time you will have less output then a 14k or lower temp bulb. You will probably be able to do SPS in the very upper part of the aquarium with a 20k bulb.

01/29/2008, 11:58 AM	#3
oct2274 Registered Member Join Date: Feb 2006 Location: Plano, TX Posts: 2,347	if you are using a magnetic ballast, I believe the XM 20k is the brightest 20k. Do not even consider the XM 15k bulb because it has horrible output and believe it or not even the 20k has more output then it.

01/29/2008, 12:10 PM	#4
DarG Registered Member Join Date: Dec 2006 Posts: 5,515	The color temp, K ratings, are very often nothing more than marketing numbers. You have to be careful. There are 15000K bulbs that actually measure 10000K and below. Some 15000K bulbs measure 20000K and over. Some 10000K's may measure closer to 15000K or actually closer to 6000K. Some 20000K bulbs may really be 15000K. The rated color temp. is very often not the true color of the bulb. Best to look at Sanjays site which is linked in the top sticky thread on this lighting forum. He has measured many of the bulbs and you can see their true color temperature as well as PAR. Make sure you pick the ballast type that you plan to use because the ballast type impacts the PAR as well as the color to some extent. BTW, the Iwasaki 15000K 175 watt bulb is one of the better bulbs on the market. Par is comparable to alot of 250 watt bulbs and color is close to the 15000K rating.