I'm not aware of there being a single correct fog colour - these sorts of things tend to boil down to artistic preference. More information on the rest of your scene/environment may well help people offer suggestions.

I'm moving this to GP&T as you may well get some better suggestions [smile]

hth
Jack

P.S. Picking a better subject line will help others direct their attention accordingly. Given you want a fast response, anything and everything you can do to help the community help you will be to your benefit.