Luxrender blueer skies help

im working on this scene

i find the skies are very dark, here are my current settings



i want a very saturated sky blue with little WHITE horrizon, not this 9pm haze.

if anyone can look at my settings and tell me how i might achieve this idd appreciate it

have you tried changing the world background of the scene? and also, how long did it take to render as it looks like a good render with that tinge of orange on the close horizon