I just purchased a house with an existing pool and learning more and more about my pool, but still have many questions. I purchased the LaMotte ColorQ 7 Plus test kit. I have run several tests with my tester, but have also taken several samples to a local pool store. I'm finding some discrepancies and puzzled what to make of them. I recently shocked the pool with calcium hypochlorite due to nearly non-existence of free chlorine with a bit more combined chlorine. I added the cal-hypo Monday evening and found free chlorine of 5.64PPM and total chlorine of 6PPM on my ColorQ. I took a sample to the pool store where they found both free chlorine and total chlorine to be both 7 PPM. I'm not exactly sure what the brand of testing they are using in the store, but it is a dip stick and colorimeter. They also have a Taylor test station that requires human interpretation, but he instinctively tossed the remainder of the sample after dipping. I find it odd that the ColorQ shows 5.64PPM when their test shows 7PPM. Whose tests should I believe?