PH tester help you to determine the exact pH value of your water. In hydroponics, this value should be between 5.5 and 6.5.
How to test?
Take a little water from the flask which flows through the column. Add two or three drops of the solution, shake and mark the color against the color card. Make sure your pH is between 5.5 and 6.5.
If necessary add pH Down to lower the pH, otherwise water to raise it.
When to test ?
Either after adding water and nutrients, or do the test once a week.