Mobile Bay Reef Keepers

We currently use 10K 175W XM bulbls. We have been satisfied with the crisp white color. I was perplexed as to whether to go with 10K's or 20K's when time to replace our bulbs. We went with 10K's. Now with more research 20K's seem to have more of my attention. What are your opinions and experiences with the bulbs. I also read 20K's produce more grow out. Andy's Blue Zoas really got my attention under 20K's as we both have the same colony frags. Does anyone by chance have a set of 175W 20K I can borrow to see for myself? Any opinions or assistance is greatly appreciated. Thanks.

Billy

I've never had 20,000K, but the ones that I have seen are too blue. I like the 6500K with lots of actinic VHOs to supplement. I also like the 10,000K without the added actinics. Just my humble and mostly worthless opinion!

IMO 20k are just too damn blue, I would go 10k all the way.

After experiencing both 10K's and 20K's, I personally like the 10K's better. Just my personal opinion.

This is one of the best links out there when you are researching the looks and PAR of different MH bulbs. The pics are pretty darn close to the actual look of the lights when running.

http://www.cnidarianreef.com/lamps.cfm

And don'y count on every 10k bulb not to be blue! My blueline 10k is almost too blue.

hmmm i wish they had one for lower powered MHs...
Well i picked my fav combo for when I get a big tank...

CoralVue 15k w. Blueline E-Ballast

Personally, I like the 13K. More of a crisp white light without too much blue or the yellowing of 10K. I think it's all a matter of what you want to see in your tank.
I take it you're a xooanthid fan? May have some light blue ones for you before too long if you want them. Sue

I believe the 10k produce better growth and 6500 even better yet but personaly I like the 20k for color...but that is just an personal choice...

Agree with Terry.... 10k's are white, 20k's are a deep blue.

ShagMan wrote:Agree with Terry.... 10k's are white, 20k's are a deep blue.

Not true. It all depends on the brand. I have seen 10ks that are bluer than some 20ks. As well as 20ks that aren't that blue. You WILL get the best growth from a 6500k, but the color isn't that nice. Everyone seems to agree that it is really a personal preference, so do I. Just don't count off a bulb simply because of it's kelvin rateing.

Blueline 10K's are like 25K's to me. Way off on the rating. But on the other hand, Blueline does make a 10K "Super White" ? or something of the sorts.

I just do not like Blueline, personally.

10k is whiter than 20k...that is not to say a 10k from one brand might be bluer than 20k from another.....but a 10k and 20k of the same brand the 20k will be bluer

Jahdiel wrote: I also read 20K's produce more grow out.
Billy

20k halides are known for producing color but not the growth that you get from 10k's.

I use 2 250 watt 6500k Iwasaki's and 4 110w VHO actinics and like the color.

We have some 6500Ks, but never tried them due to the yellow color.
You say the grow out is better with them? We have the MH's as
mentioned along with 4 Super Actinic. Do you think experimenting
with different combinations (MHs) will affect the corals?

Billy

I used 400W blueline 10K+ bulbs for about six months until I switched to XM 20k bulbs which have been in my tank for about 8 months now. Quite frankly, the color is about the same to my eyes except the XM's are obviously brighter. As far as growth I really never noticed anything until I added a calcium reactor. As far as coloration of corals, XM 20K's do, in fact, give some better color to SOME sps, but not everything. I think 20k's have gotten a bad rep from the Radium bulbs which are way too blue for my taste. The XM 20K bulbs are more like a true 14K from what I understand.

Sidney