question about color temperature

[marcus_yeh]

I have a 4x96W PC over my 75 gallon reef tank with two actinics and two Daylights which were bought from the LFS. The light bulbs have been used for 10 months, so I need to order new light bulbs. I checked the type of light bulbs, and I found the Daylights are 6700k. My question is should I keep using the 6700k? Can I switch to 8800k or 10000k? Which type of Daylight light bulb is good for the coral when being used with the actinic light bulb? Any advice will be appreciated.

 

[Clearblue303]

My tank is small(20G ) and I'm using 4x15w fluorescent strips (they do a great job for my size).
So,this is what I'm using:
- sun-glo = 4200k
- day light = 6700k
- power-glo = 18000k
- marine-glo = aprox. 20 000k (not listed,but is the blue one)
Generaly people with bigger tanks use in combination the 6700k (white) and 20 000k (blue).