General Hydroponics uses the highest quality reference solutions, allowing growers to calibrate many popular brands of PH, EC and TDS meters (NaCl scale or the 442 scale). General Hydroponics technicians check each batch to ensure that their solutions are precisely calibrated and yield reliable readings each time they are used.
General Hydroponics pH 7.0 Calibration Solution
$9.47 – $20.24
Standard reference solution for calibration of pH meters and electrode storage.