General Hydroponics

1500 PPM Meter Calibration Solution 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...

1500 PPM Meter Calibration Solution 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...