Acidity versus alkalinity are key factors in your crop's water and root zone as measured by pH. If you have too high or too low pH your crops cannot uptake nutrients and may well be damaged or even killed. That's why smart growers daily monitor and adjust optimum pH levels for hydroponics sphagnum moss coco coir rockwool aeroponics soil and other types of plant growth media. Some companies make cheap inferior pH adjustment products that never achieve consistent results; some of those products contain harmful materials. Advanced Nutrients pH products are carefully-manufactured pure concentrates that are pharmaceutical grade.