Growing plants hydroponically means using water as the growth medium rather than soil. One essential key to a functional hydroponics system is water quality monitoring. In traditional growing, plants absorb nutrients from the soil. In order for hydroponically grown plants to get the nutrients they need, the water in a hydroponic system must be nutrient enriched. Nutrient enriched water should be closely monitored and always tested to ensure that nutrient levels are not too low or too high.