Fog not changing depending of the day time?

Alright, so I tried to modifiy a little bit some day changing script to be able to change the fog properties instead of the outdoor ambient. Here's what it gave:

L = game:GetService("Lighting") 


while true do 
	wait(1)
	T = L:GetMinutesAfterMidnight()
	L:SetMinutesAfterMidnight(T + 1)
	if T < 300 then --Night time, after midnight.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 4000
	elseif T > 300 and T < 390 then --Dawn, sun rise.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 400 
	elseif T > 390 and T < 600 then --Morning.
game.Lightning.FogStart = 10
	game.Lightning.FogEnd = 200
	elseif T > 600 and T < 840 then --Day time.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 10000
	elseif T > 840 and T < 1050 then --Afternoon.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 10000
	elseif T > 1050 and T < 1140 then --Evening, sun set.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 10000
	elseif T > 1140 then --Night time, before midnight.
game.Lightning.FogStart = 0
	game.Lightning.FogEnd = 4000
	end		
end

Even though, it doesn't seem like it's working, and I tried many hours to find out what went wrong with it. Could somebody help me?