f.lux-like app for iPhone?

I'm not sure if this is the right sub to post this in but I used to have an Android phone where I installed f.lux, which was great for reading at night. I know that the iPhone has night mode but it's not nearly as powerful as I'm used to. Is there any app I can use that is similar? Or do I have another option? I usually read super late at night and I've found that the blue light filter that I had in the past helped put me to sleep whereas the iPhone one keeps me awake for much longer. Thanks!