I've been trying to dial-in my run time and % as well ... currently have it running for 4 hours in morning and 4 hours in the evening. My levels are in range but what I'm not really sure is: if I generate chlorine for 8 hours total, should I be testing levels before and after each pump run or just in the morning and evening? Its a little different to me than the add bleach at one time kind of thing.