Lighting newbie stuff ....

[BigAl07]

#1 Actinics :

Specifically what do they do? I understand that corals benefit greatly from that type of light but I see TONS of different types of actinics... is ONE type better than another or is actinic actinic?

Do the actinics give off any appreciable light in the the visible spectrum?

#2 Daylight bulbs :

I see 10K and then 12K which one gives the most visible light (maybe brightest is more accurate)?

Which one would benefit a REEF tank more?

Allen

[DrHank]

Actinics produce light in the blue spectrum. They used to be an absolute necessity for good coral growth. With the advances in modern lighting (10K, 14K, 20K) the depth of penetration has greatly improved. The K or degrees Kelvin refers to the color temperature or spectrum of the bulb. The higher the K, the deeper the light penetrates and the bluer it appears. In a good bulb, all will be equally bright but will penetrate to different depths.

Many people still use seperate actinic lighting because it increases phosphorescence and makes the corals look better. I personally like a MH in the 14K spectrum (I like the shimmer) and supplementation with T5 or PC actinics. I'm sure that many others will have their own (and different) opinions. I hope this helps.

[BigAl07]

It helps a LOT! I want my tank brighter but dont want to cut back on the light that my corals NEED!! I think when it's time to replace bulbs I may opt for higher "K" bulbs in addition to a single "Actinic"

Allen

[DrHank]

Your corals should do fine under any good MH regardless of the spectrum. Those which are found at greater depths (please don't ask me which they are) seem to respond better to the 14K and 20K bulbs. Since I realy don't know which are which without researching, I tend to go middle of the road and use 14K. Also, I think that you would be much happier with PC actinics than T5 actinics. I have both and get much more blue from my PCs. FYI, I have heard a few MH lovers who felt that the 20K was too blue.

[prow]

for you lighting the k is more for you but does effect the corals. for the greatest varienty of corals, for growth, a bulb close to 5000k-6500k rating will do the most. for colouring up atinics or higher k ratings help the greatest varienty of corals, in your eyes.. for your corals which light is better depends on which corals and what type pigmentation they have and of course your eyes. deferent zooxanthellae respond to different spectrums more so than others.

10k has less blue and purples but more greens, yellows and reds than a 20k which is mostly blues with a good amont of purples. but the 10k gives the most even all around colors, it has good amounts of all spectrums. a 3000k spectrum has spikes of reds and yellows mostly with little bits of greens but no blues or purples, a good k for red and yellow corals colouring.

on the 10k vs 12k, the 10k has alot of blue and purples and some good amount of greens. not much yellow, orange or reds. the 12k also has about the same purple but more blue and some green with reds and yellows. to me the extra blue in the 12k gives it a noticable crispy blue appearance. the 10k with looks, to me, much whiter, with the green making it look a little tinted yellow. remember to bulbs vary in there blending, not every 10k bulb is blended with the exact same spectrums. different brands have different recipes for their bulbs, even bulbs of the same brand in the same batch will vary to some degree. what i am getting at is some 10k's have a real yellow tint others not so much.

so whats the best depends on what your wanting, growth or color. its up to you, most go with color more so than growth, if that helps.

FYI dont count grow in how long or wide the corals get. that is more dependant on water flow, greater=they grow fat and meaty looking or calmer flow=skinnier longer type growths.