The good news is that the U2311H is generally pretty decent for colour accuracy out of the box. The exact settings will vary between individual units but I found it to have a slight warm tint. I would leave the contrast at the default (75 I believe) and set brightness to a comfortable level for yourself. Try setting the RGB channels to something like this:
R= 88
G= 100
B= 94
Look to see if you notice any particular colour cast. You can usually see it on whites although you may see a slight difference in colour temperature across/down the screen. The tint of the monitor (if yours does have one) should be fairly minor, though, and you probably shouldn't worry about it unless you need to do 'colour-critical' work. In that instance a colorimeter would be advised anyway

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