Hello all, I'm a swimming pool inspector and recently my employers bought a Palintest photometer. When I tested the pools for Free Available Chlorine/Total Chlorine/Combined Cl, the photometer has been giving me a 0.2 ppm Combined Chlorine reading more than the titration method.

For example, I'll get 0 Combined on the titration method, and 0.2 ppm on the photometer, or 0.3 ppm on the photometer and 0.1 ppm when I titrate. I'm wondering if the photometer is just more accurate, but I'm a bit concerned because these readings were taken on pools that historically have no Combined Chlorines (via titration method).

Does anyone have any experience switching over to photometers from titration, and can shed some light on my readings?