GH PH Manual Test Kit
To maximize plant growth, the pH level of your nutrients should be slightly acidic. Experienced growers consider the ideal pH for most crops to fall between 5.5 and 6.5. General Hydroponics pH Test Kits make pH testing easy. Simply fill a test-tube halfway with nutrient, add a few drops of pH Test Indicator, and observe the coloration of the liquid in the test vial. Many prefer pH Test Kit to expensive electronic meters because of its reliability and ease of use.