Review on 📏 Precision Calibration for Hydroponic Systems and Aquariums by Richard Marriott

Edit: Received this in May 2019 but became unstable in August 2019. An attempt was made to calibrate with packages enabled, but the meter did not show the correct PH calibration. I tried rinsing the flow meter sensor area with tap water but the readings were still erratic. The counter doesn't go until 4:00 p.m. at the start. It's unreliable. Now I use PH strips. The meter was used to test the hydroponic solution. You get 4 packs of calibration solution but I didn't calibrate, just tested with tap water, vinegar and baking soda. The readings look good to me. 6.98 for tap water, 3.3 for a vinegar solution, and 8.54 for a baking soda solution.