I've been experimenting with the Pooli app. You can overide the target values using the TFP recommended ones and the app seems to manage to that. However, I am seeing slightly different recomendations between each app. I think Pooli is managing to the mid range of the target range, wheras Pool Math recommends the minimum amount of chemical required to be in range, whether that be on the high end or low end - am I right?
In a way, I think I'd rather the app manage to the mid point as it should (I think?) provide greater buffer from exiting the range between testing days.