The Hanna unit was purchased 2 months ago, stored in storage solution, soaked in ph 7 for 2 hours before use (when new) and when placed in PH 7 or PH 10 calibration solution shows correct ph number. I work with color as part of my work (garphic design) and if I could not tell the correct color, I would be out of business. I understand it is the tone not the intensity of color - more orange is lower ph, more pink is higher ph. I guess I need another source to check my numbers - maybe a pool company. I check again this morning, the meter shows 7.6 and the drops show ~7.2! Any one lives in near me that can check their tap water so we can have standard? the meter shows 7.7 for the tap water. Regards

Amir