General Hydroponics pH 4.01, pH 7.01, 1500 PPM Solutions

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 our solutions are precisely calibrated and yield reliable readings each time they are used.