Don’t take any chances, no other nutrient solution characteristic is more important for healthy plants. Without the correct acidity/alkalinity, the ability of your plants roots to uptake critical nutrients is severely limited.
Simply dip the testing zone of the litmus strip in a sample of water or nutrient solution, hold for 3-5 seconds, and you’re done. Now remove the testing strip from the solution, and match its’ color to the pH Range Color Chart. The closest matching color is your approximate pH level. Compare this pH level to your plants required range of pH, and adjust your nutrient solution as needed.