Underwater Effect(A blue "glow")

[Dakurus]

I've seen a few maps out there that actually go underwater. When it's underwater, they have this sort of blue glow. I've been trying to figure out how to get this blue glow, but my efforts have been fruitless. Sorry for askng, but do any of you know how to add this blue "glow"?

 

[Dracula]

linar 1000 - 8000 0/125/225 R/G/B put the numbers on fog.

 

[Dakurus]

Thanks a million.