My script is meant to break when Saturation reaches -1, but it is not?

The script is meant to lower the Saturation to -1, then when it hits -1 it is meant to stop. However, it continues to lower the saturation, and does not stop.

How can I make it stop at -1?

local C = game.Lighting.ColorCorrection

script.Parent.DiseaseValues.Cure1.Colourblind.Value = false
script.Parent.DiseaseValues.DiseaseTotal.Counter.Value = 1

i = 0.5
while true do
    i = i - 0.1
    wait(1)
    C.Saturation = i
    if i == -1 then
        break
    end
end

for i=0.5,-1, -.1 do
	  wait(1)   	
   C.Saturation = i
end

Fixed