H2OPal is designed to help you achieve your daily goal throughout the course of the day.
After the day has ended the app is in "rest time". (At the moment, the latest you can set your rest time to start is 11 pm).
Here's a picture with explanations regarding the "rest time" screen:
Your water intake during rest time will still get counted and it will still show in the "list of logs".
Please also note that it's currently NOT possible to set the DAY END before DAY START. The times HAVE to reference the same calendar date so right now, for example, you can't set DAY END to be at 1 or 2 am. The latest you can set it at is 11pm.
Given how our app is currently set up there's no quick solution for this, however, we do have definite plans to improve this feature.