Basic 10000k question

What is the difference between a plain, simple 20w white flourescent and a 10000k flourescent?

I have a 54 gallon reef tank with only hardy, soft corals (mushrooms, polyps, leathers), and I am wondering whether I should replace the basic white flourescent with a 10000k. I realize there are many upgrades beyond that and tons of advice about lighting, but I haven't seen anything just addressing what a 10000k flourescent (not a compact, no special ballast, etc.) would do, if anything.

Thanks!

I also have a blue actinic in the fixture. Just wanted to know whether it made sense to replace the white with a 10000k.

Thanks.