F.lux don't work on dual monitors (laptop + external)?

First things first, this question is already asked, but is 2 years old and without an answer. Now my problem...

I have one monitor with another from my laptop. That's my workspace. But when I install f.lux the app only worked on the laptop's monitor and not on the external. Why? I tried Redshift but I can't lower down the redness on the screens and unfortunately, it works on dual monitors.

So can someone share some workaround?

Thank you.

p.s. I have Ubuntu 14.04 32bit

2 Answers

You have to install the package via apt-get and then manually download a modified version of the daemon file "xflux" (this is not the GUI) for your 32bit-System from under "xflux daemon (command line, but for X-Windows)".

I shut down the GUI before I did this and when starting it again, it worked.

I found this solution here:

Just installed fluxgui from and it seems to work fine with my 3 screens xrandr config.