Low or high pH levels affect the availability of the minerals required by the plant. The correct pH range for hydroponics is between 5.5 and 6.5, for soil it is not so critical, but generally around 6.3; outside of these figures nutrient problems will quickly occur as minerals become insoluble. The nutrient strength needs to be matched to the current stage of plant development. Too high a concentration can quickly burn a plant, whilst too low produces pale, weak growth. Measuring is knowing. Good results are attainable by anyone prepared to stick to this rule. Whimsical guesswork rarely leads to success! The Nutriculture pH Test Kit allows quick and accurate monitoring of pH levels in your nutrient solution. For accurate acidity testing follow the procedure below. •Take a 2ml sample of solution from the tank in the test tube provided. •Add 2 drops of reagent. •Shake the test tube and compare the colour against the test strip to determine the acidity. •Discard the test solution and rinse out the test tube. •Adjust the pH of your nutrients and retest if neccessary.