Just bring your attention back to the chant. It works best if you keep the conscious mind passive by allowing it to wander off you're giving yourself a mixed message. That what you are PhotoReding isn't important to you.
If you find yourslef having thoughts and ideas about the book cool, you then have a choice either go back and superread and dip the pages or bring your mind back to the chant.
Your chant could be a question relating to your purpose. If you find your mind wandering thinking about the answer it meand you've probably PhotoRead it so you may as well superread and dip if that's the only thing you were looking for.
Alex