Skysphere Zenith color problem

I have the Skysphere material, and when sun height is > 0, if I set zenith color with a dark color (ex: 0A0E11FF) is not even dark, is very open, only 000000FF works good, so, how I should fix the problem? I want a fix color of Zenith, I don’t want sun height affect my Zenith color (and horizon, etc.)