The General Hydroponics pH Control Kit makes it easy to monitor and adjust the pH levels of your nutrient solution.
To test the pH level simply fill a test-tube halfway with nutrient, add a few drops of pH Test Indicator, and then observe the coloration of the liquid in the test vial.
Use 3 drops per 5mL of solution.
Add a little ph Up when your nutrient's pH is too low. This will raise the pH to the proper level.
Add ph Down to lower the level when it is too high. pH Down uses food-grade Phosphoric acid to lower the pH to the correct level.