Pi night camera purple color

Hello I have pi night camera like this below:

but I can't understand why the color approaches purple?
how come? is there anything I can do?

This is because it is a night camera, it does not record in full colour.

If you install the 'Camera Settings' plugin, you should have an option to change the white balance mode, so it becomes a greyscale type image rather than purple.

Not quite correct, it does record in full colour but doesn't have an infra red filter so the ir reflected light causes the pink tinge

Correct, that is a night camera and thus doesnt have an IR cut filter. You will never get true color from it. Buy yourself something like arducam that has a cut filter you can control for day/night operation.