what lighting spectrum?
 

I am just wondering which lighting spectrum is the important to a reef tank?

10,000K or
6,700 K or
Atinic?

I have a 130W PC light over my 25G tank and currently use 1 tube of 10,000K and 1 tube of Atinic.

if I want to maximize the lighting, can i replace the actinic with a 10,000K PC bulb? or is the actinic equally important to reef as well?

I was thinking about using 2 x10,000K bulb for my PC light, then added a
basic 20W atinic flourescent strip light. Would this be better than my current light setup and would the atinic suffice?

Thank for your help!

thanks for the great link!

So Actinic lighting is not as important to coral growth i guess then right?

I think there are some benifits from Actinic, but it is not important and more of a personal preference type thing.

nah, but it makes for some cool colors. my plate coral is neon green under actinic, but just kinda pinkish green under 10kk

Re: what lighting spectrum?
 

This sounds like the best plan.

thanks you guys for all the help. I am confident enough to experiment with my lighting now after reading the posts.

the link you provided said 6,700K provided the best coral growth.
So I guess I will use a tube of 10,000k and another at 6,700 K then.

I'd use both 10k, you'll like the color better. The difference in coral growth might be a few millimeters over a 6 month period (exceptions might apply, but growth isn't always good)

this is a kinda of a misconception and a trade off. yes 6700K will give you better growth than a 10 K but the color of your corals will suffer. now having said that if lighting was the only thing that contributed to coral growth and color this post would be over, you also have dissolved nutrients, chemical make up of the water (PH, Alk, Ca, Na ect...) location in the tank relative to the light, and so on.

I have seen tanks with 20000K bulbs show as much growth as a tank with Iwasaki's so lighting is one of the building blocks but not everything. pick the color that you are most happy with looking at. Usually a 10K MH with VHO actinic supplementation is very appealing but some people like more blue and go with radium style bulbs and some like less blue (why I am not sure :mrgreen: ) and go with the 6500K type bulb. I personally use 10K bulbs with two 94watt VHO Actinic.

I want to emphasize what Steve and Brad were alluding to. There are few objective measurements made in this hobby, and attributing coral growth strictly to light spectrum would be a mistake. Best to worry about looks first and technical findings second in this case I think.