6700K is the absolute MINIMUM you need for aquariums, 10,000K being the preferred minimum. 5000K is not enough for aquatic life. I prefer 14,000 or 20,000K personally as they are a little more blue and make everything look better.
I use 10k bulbs without and actinics and everything grows pretty well. I like the look without actinic supplementation, but that is just a matter of opinion.