Naturally, proper fertilizer management is essential to the cultivation of healthy and high-yielding crops. This task becomes more challenging in hydroponic closed irrigation systems. The challenge rises from the fact that in a closed irrigation system there is always residual fertilizer that the plants do not consume, which over time accumulates to form an imbalance of fertilizer elements within the nutrient solution. Therefore, in closed irrigations systems the management of fertilizer very quickly become as much procedural task as it is technical. Over the past 10 years NorStar has perfected its fertilizer management solutions to tackle both challenges and successfully deployed proven technology and algorithms commonly found in NorStar's irrigation systems.