pH 4.01, pH 7.0, 1500PPM

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.


  • 8 oz
  • 1 Quart

Find a store near you that carries Reference Solutions.

For safety information:
See the pH 4.01 SDS here
See the pH 7.0 SDS here
See the 1500PPM SDS here