This Terra Aquatica General Hydroponics pH Test Kit consists of a test tube for taking a sample, a reagent liquid to add to the test tube and a colour chart showing the pH between 4.0 and 8.5, against which the colour of liquid in the test tube is matched. The pH should be tested after adding Nutrients as Nutrients can change the pH of the water. A high PH can reduce the availability of iron, manganese, boron, copper, zinc and phosphorous in plants. A low PH can reduce the availability of potassium, sulphur, calcium, magnesium and phosphorus.
If the pH moves out of the desired range, it can be lowered by the addition of pH Down to the solution, or raised by adding pH Up.