Review on Accurate Hydroponic Growing: General Hydroponics 4 01 Calibration Solution by Tim Paolucci

Noticing that all the plants were showing serious signs of stress, I ordered a new pH meter that came with the same pH calibration solutions. After calibrating the new pen in the new solution, I tested the old GH 7.01 and got a score of 7.6. The soil pH measurement showed values consistent with water that was too acidic for the root system due to the inaccuracy of the GH calibration solution. After three months with a new pen and new calibration solution every month, the plants come back with renewed vigour. Soil and sewage indicators returned to acceptable ranges.