5500k or 6500k

10k-20k seem to be the popular choice

but

has anyone used either 5500k or 6500k for acropora? if so, what were the growth rates and the total outcome from using either of these two k-values?

 

I have posted about a 100 plus times that a 65K Iwakie is the single best bulb to grow any sps or Lps or soft under replicates the suns natural rays perfectly .. But the corals are not colored up very well .. Then we take them in and set them under VHO 3 and 14K for a month or two to color them up.. A lets say blue torte won't ever look very blue under a 65K bulb.. they tend to look brown to greenish.

Another benefit for commercial growers is the Iwakie is a good work horse and burn true for up wards or 2.5 to 3 yrs.. of life span..

 

I've never run 5500's. However, I ran 6500's with VHO actinics for a long time. I got very good growth but I never measured it.

 

6500k's are yellow to the eye but corals seem to grow like mad dogs. I used to use them. There is a lot of info on them on this board including par pics if you dig.. here is one interesting link I posted some time ago:
Lighting Technical Data

 

5500k:
duplicates sunlight for the depth of 0-3' giving a yellow hue

6500k:
duplicates sunlight for the depth of 3-8' giving a yellow/white hue

but which one is the best for acropora?

and then,

as a supp, which combo is better either for T5 or pc? using either 5500k or 6500k

 

I believe Dana Riddle did a few tests in regards to growth and spectrum and I don't believe the 6500k bulbs fared as well as everyone says. I want to say that the 20,000k actually did better than a 10,000k as well.

It is an interesting read....

 

I'll say it again the 65 K Iwakie is the best bulb period for growth rates . I tested them for 2 yrs and found them to do far better then any other bulbs the 55 are a little to cool.. But be prepared to color them up under better lamps of hotter K values .. Again the 65K is best for acroporas and LPs and softs growth rates..

 

tangster:
no offense, but i need something better than, because i said so. did you also test the 5500k for 2 yrs? and if so what were the results.

dr frag:
i agree with you regarding 20k
http://www.advancedaquarist.com/2008/12/aafeature1
but, between 5500k and 6500k which is the best?

5500k has more blue and less red than 6500k