I wish you could use f.lux on an iPad without hacking it. I run the PC and Mac versions.
People should know to NEVER jailbreak your Apple iOS device - or else you seriously compromise the security of your device!
A simple solution I have been using at night with my ipad is to wear orange lens sunglasses. I have noticed a significant change in my ability to fall asleep at night since I started wearing them at night to watch TV or use my ipad. I have f.lux on my desk computer, but do not want to hack my ipad to put it on there.
I bought the glasses on Amazon for under $10.